One of the most controversial figures in the history of neo-Kantianism is Otto Liebmann (1840–1912). If we are to believe popular or textbook accounts,1 Liebmann is the very founder of neo-Kantianism. His book Kant und die Epigonen, which first appeared in 1865, is its opening manifesto. Its celebrated refrain “Back to Kant!” became the slogan for the whole movement. Such has been Liebmann’s reputation for at least the past half century.
Recently, however, Klaus Christian Köhnke, in his brilliant Entstehung und Aufstieg des Neukantianismus, has pleaded for a drastic reassessment of Liebmann’s reputation and historical significance. Liebmann’s work is hardly groundbreaking, Köhnke argues, because it comes at the end, rather than the beginning, of the first period of neo-Kantian programmatics (1849–1865).2 Furthermore, there is little of scholarly or philosophical value in his book, whose interpretation of Kant is crude and simplistic, and whose critique of idealism is tendentious and rhetorical. Köhnke’s reassessment is driven chiefly by his contempt for Liebmann’s politics. Liebmann is for him the epitome of the conservative German nationalist, a chauvinist zealot who preaches loyalty and obedience to the fatherland. Here is Köhnke’s vivid portrait of the man:
He was born in 1840 … and thus was a child of the Bismarck era: a spirited fraternity member, with moustache and short, exactly-parted hair; he looked, if the comparison could be permitted, more like a Prussian lieutenant or a German engineer on the Turkish railways than any philosopher before or after him. Mathematically and scientifically educated, Liebmann was an admirer of Treitschke and a firm hater of the French and British, though in that respect he hardly differed from the German national average. His whole style had nothing to do with an “angry young man” (Willey), but rather more to do with the ruthlessness and brutality of the central figure of Der Untertan.3
After this damning caricature, Köhnke attempts to expose the shady politics behind Liebmann’s neo-Kantianism. He maintains that Liebmann’s philosophy was motivated by a political agenda: the attempt to make Kant’s philosophy into propaganda for the new Bismarckian Reich. After all, Liebmann expressly says that the spirit of the categorical imperative appears in Prussian military discipline, in the strict obedience and complete submission of the individual to the state. Because of that agenda, the case against Liebmann, as far as Köhnke is concerned, is closed. There is little more worthwhile to say about him. Apart from a scanty summary of two of his early works, Köhnke ignores the rest of Liebmann’s corpus.
Yet Köhnke’s reappraisal of Liebmann needs reappraisal itself. To take it as the final word would not only result in a grave injustice to Liebmann but also in a drastic distortion of the history of neo-Kantianism. There can be no question that Köhnke is right to assail Liebmann’s popular reputation: he is not the founder of neo-Kantianism, and his call for a return to Kant was preceded by the manifestos of Beneke, Helmholtz, Zeller, Weiße and Fortlage. Furthermore, his critique of German idealism was nothing new, but simply carried on the tradition begun by Fries, Herbart and Beneke. The rest of Köhnke’s reappraisal is, however, groundless. The attempt to discredit Liebmann’s philosophy on the basis of his politics is misconceived: it throws the baby of philosophy out with the bathwater of politics. Politics should not be the basis for an evaluation of his philosophy, whose epistemology and metaphysics should be judged by different criteria. In any case, as we shall soon see,4 Köhnke’s account of Liebmann’s politics is not only wildly anachronistic but grossly inaccurate.
Any accurate and complete picture of neo-Kantianism demands that we give a fuller and fairer treatment to Liebmann. Even if he was not the founder of the movement, he remains a central figure in its history. He was one of the first neo-Kantians to see the problems with the psychological interpretation of Kant; he was also one of the first to provide a neo-Kantian critique of positivism; and he was one of the very few who had the qualifications to discuss the relationship between Kant’s philosophy and the new developments in mathematics and natural science. An inspiring and beloved teacher, Liebmann was an important influence upon some later neo-Kantians, among them Wilhelm Windelband, Bruno Bauch and Erich Adickes.5 Liebmann’s first book not only created a stir, but some of his later writings were widely read, often discussed and favourably reviewed. Last but not least, it is necessary to add that Liebmann was the best writer of the neo-Kantian tradition. In a tradition not distinguished for stylistic grace, Liebmann’s writings stand out for their elegance, urbanity and wit. Though his style is popular, it sacrifices nothing in philosophical rigour and subtlety.
Seen from a broad historical perspective, Liebmann reveals himself to be a transitional figure in the history of neo-Kantianism. His work appears between the psychological-physiological phase of Kant interpretation, which prevails from the 1790s through the 1860s, and the epistemological phase, which was dominant from the 1870s to 1890s. Caught between these phases, Liebmann’s work shows traces of both. He believed that the new physiology could confirm the fundamentals of Kant’s epistemology; but he also stressed the sui generis epistemological dimension of transcendental philosophy. There is a tension in Liebmann’s work between a physiological and epistemological interpretation of transcendental philosophy, a disparity which he struggled to resolve. In his later years Liebmann stressed the epistemological side of Kant’s philosophy, which he saw as its chief intention, and he sharply distinguished between the normative and natural, questions of value and fact. In these latter respects his work anticipates that of Windelband and Cohen.
From 1859 to 1864 Liebmann studied philosophy, mathematics and natural science at Jena, Leipzig and Halle. In Jena Liebmann was a student of Karl Fortlage and Kuno Fischer, who were decisive in shaping his own neo-Kantian programme.6 At Leipzig he attended the lectures of Fechner and Drobisch, who taught him the basis of the new psycho-physics and the mathematical approach to psychology. In 1864 Liebmann became a Privatdozent in Tübingen, where he habilitated the following year. After a short stint in the military in 1870, Liebmann became extraordinary professor in Straßburg in 1872, then ordinary professor in 1878. In 1882 he returned to his alma mater, Jena, serving as professor there until his death in 1912.
It is questionable whether Liebmann had a consistent systematic philosophy. He regarded a complete system as an ideal he could approach but never attain. His style of philosophizing was to approach problems analytically and piecemeal, and he constantly stressed how his results were provisional, depending on the results of future enquiry. The lack of consistency and system is most apparent from Liebmann’s philosophical development, which largely consisted in the rediscovery and reaffirmation of something he had initially repudiated: metaphysics. Liebmann began his career with an almost positivist contempt for metaphysics, with a brusque dismissal of the relevance of the transcendent; but he ended it with a convinced defence of metaphysics and an almost pious acknowledgement of the value of the transcendent. The fear of materialism, and the aversion to positivism, pushed him away from his former “tough-minded” neo-Kantianism, which paid little heed to moral values, and towards a more “tender-minded” neo-Kantianism, which gave a central place to moral value in the universe.
Our task in this chapter will be to provide a reassessment of Liebmann’s place in the history of neo-Kantianism. We will consider the main phases in his philosophical development from a close study of his major writings from 1865 to 1900, from his early Kant und die Epigonen until his Gedanken und Thatsachen, his last major work. Our chief focus will be Liebmann’s epistemology and metaphysics, which is where his main contribution lies. On no account does our study pretend to be complete or exhaustive, to do justice to all the nuance, subtlety and detail of Liebmann’s thinking. We attempt to provide only an introduction for some of its chief themes.
Liebmann shot to fame in 1865 with the publication of his first book, Kant und die Epigonen.7 The book was a sensation, partly because of its lively and engaging style, partly because of its passionate stand on behalf of Kant. The young author, then only twenty-five years old, preached that Kant was the be-all-and-end-all of philosophy—“the most important thinker of Christian humanity”—and that every attempt to go beyond him had ended in disaster. Fichte, Schelling, Hegel, Schopenhauer, Fries and Herbart—all these epigoni had failed to surpass Kant. The proper direction for philosophy was not forwards beyond Kant but backwards towards him. No work of scholarship, still less a contribution to Kant philology, Kant und die Epigonen is more a manifesto, a feisty polemic on behalf of Kant. What Liebmann lacked in scholarly depth he made up for in rhetorical flair. His style is emphatic, witty and humorous. And just to make sure no one mistook him for a literary naif: the tract is sprinkled with quotations in English, French, Italian, Greek and Latin. Each chapter ends with the refrain “Es muß auf Kant zurückgegangen werden.” Its shorter version—‘Zurück zu Kant!’—, though more famous, was never used by Liebmann.
The title of Liebmann’s tract—Kant und die Epigonen—seems to belittle Kant’s successors. It is as if the author intends to diminish their reputations so that they do not presume to stand above his hero. The word Epigone suggests as much, because it means in modern German “an imitator without creativity” (Nachahmer ohne Schöpfungskraft).8 There is good reason to assume, however, that Liebmann did not intend the word in that derogatory sense. Bruno Bauch, the editor of the later Kantgesellschaft edition of Liebmann’s book, tells us that he meant it in the original Greek sense, according to which it signifies only “those born afterward”.9 Nothing more upset the older and wiser Liebmann, Bauch informs us, than the widespread view that he had treated Fichte, Schelling and Hegel as disrespectfully as Schopenhauer once had.10 The content of the book bears out Bauch’s interpretation. Liebmann is careful to say in his introduction that his epigoni—Fichte, Schelling, Hegel, Fries, Herbart and Schopenhauer—were all “independent thinkers” and “great architects” of their own original systems (8). And he often distanced himself from Schopenhauer’s diatribes about Fichte and Hegel, which he found “inexcusable” (76, 157–158, 214). Liebmann chose “epigoni” more to stress the dependence of these philosophers on Kant, and his careful examination of their systems shows that he does indeed respect them.
An essential part of Köhnke’s reassessment of Liebmann is his appraisal of his first book. As we have seen, Köhnke questions its historical significance, because it came not at the beginning but the end of the early period of neo-Kantian programmatics. But he also deprecates the intellectual content of the book. Liebmann’s interpretation of Kant, and his polemics against the post-Kantians, are, in his opinion, crude, rude and tendentious. Liebmann had no real interest in questions of Kant scholarship, he says, because his true agenda was political: the attempt to popularize Kant on behalf of the authoritarian Wilhelmine state.11 The only significant feature of Liebmann’s book, in Köhnke’s view, is that scholars had made so much out of something so insignificant.12
Here again Köhnke’s political convictions trump his historical sense. He goes too far in belittling the impact of Liebmann’s book. Though it was not the first manifesto of neo-Kantianism, it is still of some historical significance, partly because it was widely read and attracted much attention in its day, and partly because it was prized by later neo-Kantians, most notably Wilhelm Windelband and Bruno Bauch.13 Köhnke’s attribution of a political agenda to the work is also a misreading, because, as we shall soon see, Liebmann developed his political views only later in response to the military situation of 1870. It is for this reason that there is no mention of politics at all in the book—a very puzzling feature on Köhnke’s reading. Though Köhnke is correct in pointing out the brashness of Liebmann’s polemics and the weaknesses in his interpretation of Kant, he is also unfair in dismissing the work’s intellectual qualities. For all their passion and conviction, Liebmann’s polemics sometimes do strike their target; and his interpretation of Kant is in an important respect groundbreaking. For Liebmann saw more clearly than most of his contemporaries that there are serious shortcomings to the psychological interpretation of Kant, which was the predominant interpretation of the 1860s; he recognized before Cohen and Windelband, if only through a glass darkly, that transcendental philosophy is more epistemology than psychology.
Liebmann wrote his book in response to the philosophical situation of the 1860s. The context and content of his book suggests that it was written in response to the Trendelenburg–Fischer dispute, which had been set on its fateful course in the early 1860s.14 As a student of Fischer, to whom he felt greatly indebted, Liebmann would have wanted to defend the position of his teacher against Trendelenburg. The motive for Liebmann’s critique of the thing-in-itself would be to undermine the very possibility of Trendelenburg’s third alternative, which stipulated that a priori forms of sensibility correspond with things-in-themselves. If there are no things-in-themselves, then the a priori forms of space and time would have to be true of appearances or experience alone. In that case Fischer would win out over Trendelenburg almost by default.15
The explicit explanation that Liebmann provides for his book is that it is a response to the current crisis of philosophy. Like Fischer and Zeller, Liebmann is greatly worried by the decline in prestige of philosophy, which seems increasingly dispensable to the public. In his introduction he complains about the recent general mistrust towards philosophy. The public are either indifferent about it or, even worse, they are tempted by materialism (5). The main reason for this loss of confidence Liebmann finds less in the danger of obsolescence than in the interminable strife between the new systems. People listened in awe to Schelling’s oracles–only for Herbart to condemn them as nonsense. They were astounded by the boldness of Hegel’s dialectic–only for Schopenhauer to dismiss it as hocus-pocus. They read Fries’ polemics against Fichte, Schelling and Hegel; but then they heard about Herbart’s critique of Fries, and finally Schopenhauer’s diatribes against them all. And so the general picture is one of confusion and chaos:
Sadly, the Babylonian tower of German philosophy in our century is distinguished from the biblical one not only in that its builders believed they really reached heaven, but also in creating a confusion of thought as well as a confusion of tongues. (6)
What is the path out of this predicament? Liebmann has the same advice as Fischer and Zeller: go back to fundamentals, return to the common starting point of these systems. Those fundamentals, that starting point, lie with Kant’s philosophy. All forms of recent philosophy are only so many interpretations of Kant, so that to see what is right or wrong with them it is only necessary to go back to him. If we know what is valid or invalid in Kant’s philosophy, we will have a criterion to measure the value, or lack thereof, in all forms of recent philosophy (13).
What, then, is right, and what is wrong, with Kant’s philosophy? Liebmann is entirely confident that Kant’s philosophy is sound and solid in its basic principles. That the a priori forms of sensibility and understanding are necessary conditions of experience; that the object and subject of knowledge are interdependent; that there cannot be knowledge beyond possible experience; that human forms of representation are limited to time and space; that the transcendental subject is the ineliminable condition for all experience—all these principles are incontestable, the starting point for any sound philosophy (20–26). Showing their truth constitutes Kant’s “epoch making” achievement. Kant has done for the philosophical world what Copernicus and Columbus did for the physical world.
Still, Kant’s philosophy is not without its flaws, it too is not above critique. For one thing, it is marred by its technical terminology, artificial symmetries and rigid systematics. Behind all that rococo ornamentation, Liebmann writes, “we can almost physically detect the powered and bewigged Magister” (12). More importantly, however, there is another major flaw, one that lies deep in the Kantian system “like the worm in the fruit” (26). This is the postulate of the thing-in-itself. This postulate is the thesis that reality in itself, apart from and prior to cognition, is utterly unknowable, and unknowable in principle. This thesis is problematic, Liebmann argues, because it is utterly inconsistent with Kant’s fundamental principles, especially the limitation of knowledge to possible experience. If all that we know to exist is within experience, how do we know of the existence of the thing-in-itself, which ex hypothesi exists beyond experience? Hence Liebmann demands that the thing-in-itself be expurgated from the body of Kant’s philosophy. The only reason that Kant postulated it in the first place was to serve as “a transcendental scarecrow” to frighten the rationalists from speculating beyond the limits of possible experience (205). But the concept backfired, because the epigoni took the scarecrow for “a signpost pointing to the irrational beyond”.
Armed with this account of Kant’s insights and illusions, Liebmann had his criterion to determine the merits and shortcomings of all forms of recent philosophy. All are illusory, Liebmann argues, because they amount to so many attempts to know the thing-in-itself. There are four directions to modern philosophy, each of which has its own formulation for the thing-in-itself. There is the idealist direction of Fichte, Schelling and Hegel, which interprets the thing-in-itself as the absolute; there is the realist direction of Herbart, which turns things-in-themselves into simple real substances; there is the empiricist direction of Fries, which re-invokes the thing-in-itself as the object of faith; and finally there is the transcendent direction of Schopenhauer, which construes the thing-in-itself as the will. Once we have seen how each of these systems ends in conceptual disaster, Liebmann argues, we will see that there is no point in trying to go beyond Kant, and no alternative but to go back to him. Accordingly, each chapter of Kant und die Epigonen is devoted to a critique of one direction of recent philosophy.
It is in Liebmann’s critique of post-Kantian philosophy that we find the most daring and provocative aspect of his book. For the most part, Liebmann shared, and was indeed indebted to, Fischer’s interpretation of Kant. Like Fischer, he saw Kant’s theories of space and time as the very heart of Kant’s transcendental idealism; and he stressed the ineliminability of the knowing subject and the limitation of knowledge to experience. It was indeed Fischer who had argued that the very concept of the thing-in-itself is unintelligible and has to be eliminated because it is incompatible with Kant’s critical principles.16 Yet, despite these deep Kantian strains in his thinking, Fischer continued to be a Hegelian in his metaphysical views. The 1865 edition of his Logik und Metaphysik persisted in its Hegelianism despite its endorsement of central Kantian doctrines.17 It was in just this respect that Liebmann was taking issue with his former teacher. The hidden but pointed message behind his critique of Hegel was that Fischer needed to abandon his Hegelianism. If Hegel’s metaphysics is a gigantic attempt to know the thing-in-itself, then it is a misconceived enterprise which needs to be aborted. Liebmann was in effect telling Fischer: “if you accept Kant’s critical limits, you also cannot be a Hegelian metaphysician.” In calling for a return to Kant, Liebmann was making a plea to his old teacher, begging him to take his critical principles to their ultimate conclusion.
Whoever its intended audience, the chief contention of Liebmann’s book seems deeply paradoxical. If Kant is the source of the postulate of the thing-in-itself, and if all forms of recent philosophy go astray because they rehabilitate this postulate, why go back to Kant? It would seem better to go forward with a new philosophy rather than returning to the old one, which has been the source of so much trouble. The solution to the paradox is Liebmann’s tacit assumption that Kant’s postulate is dispensable. We can have the core of Kant’s epistemology without the thing-in-itself, Liebmann assumes. Indeed, since the postulate is inconsistent with Kant’s basic principles, we not only can but must get rid of it.
But that answer only poses another question: If the thing-in-itself so blatantly violates Kant’s principles, why did he postulate it in the first place? Liebmann owes us an explanation. To his credit, he attempts to provide one, indeed two. He thinks that there is both a historical and psychological explanation for Kant’s unseemly postulate. The historical explanation is that Kant could not completely renounce the language of the Leibnizian-Wolffian system if he were to be intelligible to his age (35–36). The thing-in-itself was an old tattered hand-me-down: the ens per se of Wolffian ontology. Kant kept using it so that he could warn the Wolffians that what they were trying to know is really unknowable. The psychological explanation lies in our deep-seated human tendency to ask the question ‘Why?’, even when we know we cannot answer it (51–66). The final goal of all knowledge is to know the unconditioned, that which completes the series of conditions. The thing-in-itself is just another concept for the unconditioned. We are led by a very natural chain of reasoning to assume its existence. The reasoning goes: everything conditioned depends on something outside it as its cause; the empirical world in space and time is conditioned; therefore it depends on something outside it as its cause (38).
Whatever Kant’s reason for postulating its existence, Liebmann was confident that the thing-in-itself could be easily removed from the corpus of the critical philosophy. But here his confidence bordered on the rash and reckless. It is remarkable that, throughout Kant und die Epigonen, Liebmann does not consider Kant’s major motive for postulating the thing-in-itself: the need to make room for faith. It is as if Kant’s entire concern with morality and religion were misconceived. Liebmann’s justification for this apparent neglect seems to be that if the thing-in-itself is inconceivable, then it cannot be an intelligible object of moral or religions belief. On just these grounds, he mocks Fries for having made the thing-in-itself the object of religious faith (156). In general, Liebmann had little sympathy for Kant’s attempt to rescue morality and religion with the thing-in-itself, which he dismissed as “the feeble side of this great thinker”.18
It is even more remarkable that Liebmann does not attempt to reconstruct, and then deconstruct, the line of reasoning that led Kant to postulate the thing-in-itself in the first place. However problematic, the thing-in-itself is hard to avoid on Kantian premises. If 1) the forms of intuition and understanding condition how the world appears to us, and if 2) they do not create the manifold of intuition, which has to be given to us, then it only seems natural to assume that 3) there is something that exists apart from and prior to the application of these forms. This something will be unknowable to us because the a priori forms of intuition and understanding condition and therefore alter what they know. Strangely, Liebmann accepts both premises yet denies the conclusion.
The question still remains: Why does Liebmann think the thing-in-itself is inconsistent with Kant’s principles? This claim too is controversial and stands in need of justification. Liebmann is largely content to reaffirm G.E. Schulze’s arguments in Aenesidemus (49–51). Schulze had maintained that Kant has no right to assume the existence of the thing-in-itself, or to hold that it is the cause of our experience, because this amounts to a transcendent application of the categories of existence and causality beyond experience.19 Although Liebmann endorses these now standard arguments, he thinks that Schulze is far too tentative. While Schulze holds that it is still possible for the thing-in-itself to exist, limiting himself to saying that Kant cannot provide a justification for its existence, Liebmann corrects him by adding that it is completely absurd to think that the thing-in-itself could exist at all (51). The thing-in-itself is sheer nonsense, a “contradictio en adjecto”, “wooden iron” (27).
Whence this stronger claim? Liebmann sometimes writes as if it were self-evident because to postulate the unthinkable is already to think it, which is contrary to its unthinkable nature (27). This was an old criticism of the thing-in-itself, one already made by Fichte and Hegel, and one reaffirmed by Fischer. But, however venerable the tradition behind it, the criticism rests on a simple confusion: it confounds the concept of the thing-in-itself (its sense or connotation) with the thing it intends to designate (its reference or denotation). While ex hypothesi we cannot think of the object designated by the unthinkable, we can think of the concept of the unthinkable; otherwise, even the claim of its unthinkability would make no sense.
Fortunately, however, Liebmann does not leave it at this, and goes on to provide two more substantial arguments for his stronger claim. 1) According to the Transcendental Aesthetic, all representations conform to the a priori forms of inner sense, space and time. We therefore cannot represent something existing beyond space and time; so it is impossible for us even to represent the thing-in-itself, which is ex hypothesi beyond space and time (26–27). 2) We assume that the entire realm of experience is conditioned and that there must be something unconditioned as its source, which would be the thing-in-itself. But the concept of the conditioned has meaning only within experience, that is, with regard to particular events, so that it cannot be applied to experience as a whole (39). In other words, experience is conditioned only in its “immanent constitution”, by what lies within itself and not by what lies beyond itself. It makes no sense to seek for a cause of experience as a whole because the category of causality has meaning or significance only within experience.
There are serious weaknesses to both arguments. First, Liebmann simply ignores Kant’s reply to these criticisms in the preface to the second edition of the Kritik: that it is necessary to distinguish thinking about the thing-in-itself from knowing it (B xxvi). Kant explained that all his restrictions against knowledge of the thing-in-itself did not forbid the possibility of thinking about it according to the categories of the understanding. Second, Liebmann’s argument from the Transcendental Aesthetic equivocates with the concept of representation, which might mean the possibility of imagining something or the possibility of even conceiving it without contradiction. The Aesthetic indeed shows that we cannot imagine something that is not within space and time; but these limits of the imagination do not hold for the pure concepts of the understanding, which can be meaningfully extended beyond experience, even though they are then without any reference and so cannot provide knowledge.
Fortunately, the most important and interesting contribution of Liebmann’s book does not rest on his arguments against the thing-in-itself. Rather, they lie elsewhere: in his critique of psychological interpretations of Kant. Liebmann criticizes Schulze, Schopenhauer and Fries for interpretating Kant’s philosophy as if it were a kind of empirical psychology, little more than an investigation into the faculties of the mind. He makes two basic points against this interpretation. First, it is a mistake to equate, as Schulze and Schopenhauer do, the a priori with the cause of experience, or with an innate mental capacity (45, 183–185). Rather, the a priori signifies the logically necessary conditions for knowledge of experience. Kant’s central concern is not with the origins or causes of experience but the truth conditions for empirical judgements. Second, it is also an error to assume, as Fries does, that we can determine the general principles of epistemology from empirical enquiry, from inner observation and inductive generalizations. These methods give results that are only particular and contingent; but the general principles of experience are synthetic a priori, claiming a universal and necessary validity (147–149).
The ultimate lesson of Liebmann’s critique of Schulze, Schopenhauer and Fries is that Kant’s transcendental philosophy is more than psychology for the simple reason that it is supposed to investigate the very possibility of psychology. An empirical psychology cannot replace transcendental philosophy because it presupposes the very methods and principles that transcendental philosophy should investigate. In making this point Liebmann anticipated the later interpretations of Kant of the Marburg and Southwestern schools. Unfortunately, in Kant und die Epigonen Liebmann did not develop a more positive account of transcendental enquiry and how it differs from empirical psychology. We are left with a negative message with little more than vague suggestions about the distinctive status of transcendental enquiry itself. This was a shortcoming that Liebmann would address in later writings.
Seen from a later perspective, Kant und die Epigonen was a rash and reckless work, altogether the product of a tempestuous young man. Its arguments against the thing-in-itself are weak; it had failed to develop the implications of its critique of psychologism; and it had brushed aside Kant’s moral and religious concerns. The older and wiser Liebmann admitted his youthful folly and dismissed the work as a “Jugendarbeit”.20 He quickly learned the errors of his ways. Soon he would see the need for the concept of the thing-in-itself, which he had too quickly dismissed; and soon he would grow to appreciate Kant’s concern for morality and religion, which he had too readily rejected. We can well say of Liebmann what Hegel once said of Schelling: he made his philosophical education before the public. This is the classical problem of publishing too young. We shall soon see how Liebmann learned this bitter lesson.
In the concluding chapter of Kant und die Epigonen Liebmann begins to reveal some of the moral motivation behind his diatribe against the thing-in-itself. The Kantian Copernican Revolution in philosophy had shown that man is the centre of his universe, and that he cannot go beyond the limits of his experience. For Liebmann, this fundamental epistemological lesson should also be an ethical one: that we should make man the centre of our universe. All of our problems, as Liebmann puts it, are ultimately “immanent”, that is, they are problems only for we human beings who exist in space and time, and which we should strive to solve in the here and now (208, 212). We should not trouble ourselves, then, with metaphysical or theological speculation about a transcendent realm beyond our human world. In advocating this ethical doctrine, Liebmann was reaffirming, if only implicitly, the old tradition of German anthropology, the tradition of Herder, Schiller, Platner, Fries and Beneke. That tradition was always profoundly humanist, preaching that philosophy should be not only about man but also for him.
But Liebmann had even deeper moral motivations for his campaign against the thing-in-itself. The problem was not simply that speculation about the transcendent drew attention away from the immanent human realm. More gravely, it could also undermine the moral convictions that we need to act within this realm, more specifically, the beliefs in human freedom and responsibility. Kant had postulated his noumenal realm precisely to rescue these beliefs from the determinism of the natural world. But Liebmann was convinced, for reasons we shall soon see, that Kant’s strategy had backfired. His doctrine of transcendental freedom did not support but undercut our beliefs in moral freedom and responsibility. So, unless we eliminate the noumenal realm, which is the basis for that doctrine, we jeopardize some of our most important moral beliefs.
To save the concepts of freedom and responsibility for the immanent realm, to rescue them from the perils of the transcendent, Liebmann wrote another book, his Ueber den individuellen Beweis für die Freiheit des Willens,21 which appeared in spring 1866, only one year after Kant und die Epigonen. This tract is a caustic critique of the concept of transcendental freedom and a dogged defence of a compatibilist conception of human freedom. Liebmann’s intent is to save freedom and responsibility within the immanent domain, which is also for him the realm of nature where all events are determined according to causal laws. The ultimate message of the book is that there is no need to postulate a transcendent will to save freedom; indeed, that the concept of noumenal freedom undermines the facts of moral consciousness and the real relative freedom that we do possess.
The dangers of the doctrine of transcendental freedom were apparent to Liebmann less from Kant himself than his cranky would-be heir, Arthur Schopenhauer. It was Schopenhauer who seemed to take the Kantian doctrine of transcendental freedom to a radical and absurd extreme, violating our normal moral intuitions and undermining our beliefs in freedom and responsibility. Schopenhauer’s popularity in the 1860s had also made him an inviting and important target. Liebmann had already subjected Schopenhauer’s metaphysics to sustained criticism in the longest chapter of Kant und die Epigonen.22 In his new book he turned against Schopenhauer’s moral philosophy, which seemed to him the best example of how excessive metaphysical speculation is a danger to morals.23 Liebmann specifically targets Schopenhauer’s 1839 Preisschrift über die Freiheit des Willens,24 which had discredited the testimony of self-awareness as an arbiter of the question of free will. Schopenhauer argued that my self-awareness does not give me evidence for the power of choice, the ability on any specific occasion to choose between X or not-X.25 Liebmann wishes to restore the worthiness of that testimony, so that each person has within his own consciousness “an individual proof of the freedom of the will”.
As Liebmann portrays it,26 Schopenhauer’s theory of the will is a heavy and harsh determinism. It maintains that a person’s actions are the necessary result of his character and motives. A person’s character is given at birth and normally unalterable, the result of the transcendent will expressing itself through him.27 Given his character, a person will choose to act only on certain motives rather than others; and given his character along with these motives, his action follows of necessity, such that it could not be otherwise. One and the same person, with the same motives and under the same circumstances, must always act in the same manner.28 When we feel that we could have done otherwise, we are simply ignorant of our own character and the causes compelling it to act in just one manner. Belief in the liberum arbitrium indifferentiae—the power to act and choose equally between two alternatives—is an illusion, arising from confusing the correct proposition “I could have done otherwise on this occasion if my character were different” with the incorrect proposition “I could have done otherwise on this occasion with my present character” (62). I am responsible, Schopenhauer thinks, not because of what I do but because of the kind of person I am (68). It is the character, rather than the deed, that is the ultimate subject of moral praise and blame.29
So far this seems to be straightforward and unqualified determinism, one that stresses the role of character in the necessity of human actions. Yet, as Liebmann notes, Schopenhauer qualifies his determinism in one important respect (94–97), namely, he allows a person, in rare moments of great insight, to see through to the source of all suffering and to deny the will to live, which otherwise determines his phenomenal character. When a person finally realizes the futility of life, the nothingness of individual existence in space and time, or when their own will has been broken by suffering, they can elevate themselves to a moment of “transcendent change”, which involves “the complete annulment of individual character”.30 In these cases a person does have the power to transform his character and to change his life. And so there was something like moral redemption in Schopenhauer’s universe after all, though it came from a conversion as mysterious and magical as that of divine grace.
Liebmann is sceptical of such mystical transformative experiences, which he finds hard to square with Schopenhauer’s general determinism (94–95, 97). But in some important respects he agrees with Schopenhauer’s theory of the will. He too finds the liberum arbitrium indifferentiae unacceptable, and he too affirms a universal cosmic necessity. Any tenable theory of freedom, Liebmann believes, has to be compatible with the general determinism of nature, which ultimately derives from the principle of sufficient reason itself. Yet, beyond these points, Liebmann’s agreement does not go. He maintains that Schopenhauer had pushed the case for determinism too far, to the point that it violates the testimony of our normal experience. The task of a moral theory is to explain this experience, not to dismiss it as an irrelevance if it contradicts the dictates of our theory. Schopenhauer’s theory contradicts, blatantly, our normal moral consciousness, Liebmann contends, because it makes nonsense of our common practice of praising right actions and blaming wrong ones (71–72, 75). What is the point of such praise and blame if, as Schopenhauer holds, our characters are completely unalterable? Surely, the purpose of our moral practice of praise and blame, approval and disapproval, is to change our characters, to make us act differently the next time. But, barring some bizarre mystical insight, Schopenhauer does not allow this kind of change to occur.
Is it truly the case that our normal characters are as unalterable as Schopenhauer portrays them? Liebmann doubts that this is the case. He maintains that we do constantly change our character in the course of our normal moral development, that character alters with the growth of knowledge, experience, education (96). This makes Schopenhauer’s determinism incorrect in one important respect: the same person need not always act in the same way under the same circumstances.31 Since the person can change his character, he or she can act differently the next time in the same circumstances (99). This goes some way to explaining, Liebmann believes, our common moral conviction that we could do otherwise. Though we cannot do otherwise on the same occasion, at one and the same moment of time, and with the same character, we can still do otherwise in the future once we change our character.
The least acceptable side of Schopenhauer’s moral theory Liebmann finds in its metaphysics, specifically its doctrine of a transcendent will. The reason I am the kind of person I am, Schopenhauer holds, rests on my intelligible or noumenal character, which, through “a supertemporal act of will”, ultimately drives my phenomenal character (68).32 This act of will is, however, unknowable to me, because it is the basis of all consciousness and as such transcends it (69). Such a doctrine, Liebmann protests, undermines all our normal intuitions and feelings about moral responsibility. It means that I, as a rational self-conscious person, should be responsible for an action even though I do not know its ultimate source, a supertemporal act of will. It is absurd, however, to be held responsible for something I could not know myself to do. The fundamental condition of all responsibility, Liebmann contends, is self-consciousness, the awareness of my doing something and consciously choosing it as my course of action (10). But this condition is violated by Schopenhauer’s supertemporal act of will, which directs and controls my life even without my knowledge.
The ultimate source of Schopenhauer’s determinism, Liebmann stresses, lies in his metaphysics, and especially in his theory of the will. This theory postulates the existence of a single universal impersonal will in all human beings and throughout all of nature, which is the ultimate source of each person’s individual character. This theory poses a grave danger to our beliefs in personal freedom and responsibility, because this will creates our character and makes us act in ways of which we cannot be self-conscious and so cannot control. Whether rightly or wrongly, Liebmann is clear in blaming this metaphysics for Schopenhauer’s harsh determinism: “From the wind-egg of so-called transcendental freedom the supposed absolute unfreedom of will and action is demonstrated [on Schopenhauer’s theory]” (81). Here we see explicitly articulated the motive for Liebmann’s campaign against the thing-in-itself: transcendent freedom, the most important form of the thing-in-itself, does not save but undermines human freedom.
Attempting to defend a completely immanent theory of freedom—one that dispenses with its illusory transcendent dimension—Liebmann advances a form of compatibilism according to which our actions are still free even though they are determined of necessity according to the laws of nature. It is possible to overcome the dilemma between determinism or indeterminism (i.e. belief in uncaused causes), Liebmann argues, by questioning the common premise of both these dire alternatives: that the necessity of an action amounts to a form of constraint or compulsion (122–123). The incompatibilist insists on uncaused causes as a condition of freedom, and the determinist attempts to eradicate freedom entirely, because both wrongly equate necessity with constraint. Deny that common premise and the middle path is clear. It is only necessary to recognize, Liebmann contends, that for an action to be determined does not mean that it is coerced or constrained. Coercion or constraint makes sense only when I cannot do that which I will to do; but it is still possible for my decision and action to be necessary, the product of strict natural laws, and for it to be what I want to do. I am constrained or coerced only by a necessity that I have not willed, one that rules against my will (122). But if there is sometimes a necessity that rules within me—through my will—then there is no constraint or coercion at all. It takes the fear away from determinism, Liebmann thinks, once we realize that our wills too are necessary moments in the causal chain of nature. Our wills are indeed determined, a product of everything that has happened before them; yet it is still the case that they too are causes of action, that without them the action would not follow; they are still a necessary, though not a sufficient, condition of action (118, 128).
Much could be said on behalf of Liebmann’s second book. His critique of Schopenhauer is compelling, at least in places, and his compatibilist theory of the will is plausible; and, as usual, the argument is put forward with great clarity and vigour. Yet at the close of his Beweis Liebmann undermines the very freedom he was so intent on defending. Throughout his book he aspired to explain the facts of moral consciousness, to uphold the common belief that we are the causes of our actions and that we have the power to do otherwise. While he rejects the liberum arbitrium indifferentiae, he does want to make sense of the power we have as moral agents to change our lives and to act otherwise on future occasions. Yet Liebmann undermines his own project by arguing at the end of his book that for an agent to be free he or she has to act morally, that is, to follow maxims that impose the moral law upon his or her will (128–131). If we are to be free, he stresses, we should have the power to resist inclination and to act according to reason alone (128). This was the old Kantian thesis, put forward in the Kritik der praktischen Vernunft, that freedom of will consists in moral autonomy, the power to act on the categorical imperative. As a Kantian, Liebmann finds that an admirable thesis, and duly makes it part of his own theory of freedom. Yet this thesis has a disturbing consequence: it undermines freedom because it means that a person is free only insofar as he or she is moral, that someone is not free if he or she is immoral; in other words, there is really no freedom of choice at all. If we are to be free, however, we must be free in choosing either of two alternatives, whether right or wrong. Kant himself had seen through this problematic consequence of his original theory of freedom and accordingly revised it in his Religion. Liebmann, though, fell into the old error, undercutting the freedom of choice that had been his original intention to uphold.
One could say of Liebmann’s Beweis what he had said of his first book: it too was a “Jugendarbeit”, the work of a youth. For Liebmann did not remain true to his own critique of transcendent freedom. In a much later essay we find him defending as the source of human freedom “that mysterious something that thinks the ‘I am’ and ‘I think’ without knowing in what it ultimately consists and what it really is”.33 For reasons we shall soon see, Liebmann found it necessary to transcend the limits of his own philosophy of immanence.
In the late 1860s Liebmann failed to develop his promising critique of empirical psychology suggested at the close of Kant und die Epigonen. That critique invited the prospect of a new epistemological account of transcendental philosophy, one that broke finally with the psychologistic mould established by Fries in the 1790s. Yet this was the 1860s and the hold of the empirical sciences over philosophy was still far too great to move in such a new direction. Rather than shunning empirical psychology, Liebmann remained in her embrace. For his next work on transcendental philosophy was a foray into a psychological domain, the theory of vision. In the tradition of Descartes’ Dioptrice, Berkeley’s New Theory of Vision and Schopenhauer’s Über das Sehen und die Farben, Liebmann’s Ueber den objectiven Anblick explores the epistemological implications of visual psychology.34 Its chief aim, as Liebmann explains in its ‘Vorwort’, is to show that exacting empirical research into human physiology provides decisive evidence against realism and for “an idealistic worldview” (iv–v). In embarking upon such a project Liebmann seems to have been inspired by the latest work on visual psychology, by the research of Lotze, Müller and Helmholtz, whose work he often cites.
Another motive for Liebmann’s new work, though never made fully explicit, was to fill an enormous gap in the argument of his Kant und die Epigonen. Though Liebmann wanted to convince all philosophers of the need to return to Kant, he had not really provided any positive argument for doing so. Incredible sed verum: Liebmann had still not vindicated Kant’s basic principles! Kant und die Epigonen was a polemic against speculative positions, and it suggested the truth of the critical one only by default. Worst of all, the battle against materialism was not joined in the least, for there was nothing to stop a materialist from happily endorsing Liebmann’s critique of the epigoni while snubbing his nose at Kant himself. Hence Ueber den objectiven Anblick would go the extra step further to provide a positive argument for Kant’s basic principles. Now the materialists will be fought with their own weapons: the results of scientific research.35
The first chapter of Ueber den objectiven Anblick is devoted to the physiological conditions of sense perception. Liebmann lays down all his cards at the very beginning by stating two fundamental principles. The first principle is perfectly straightforward: that sense perceptions are representations in us. The second principle, however, is more controversial: that the content of sense perception consists in nothing more than inner states; in other words, what we see, sense qualities such as colours, sounds and smells, are “affections of the psychic subject” (3). While the first principle is compatible with idealism or realism, the second is incompatible with direct realism, the thesis that what we sense is nothing less than qualities of objects themselves.
Though it is more controversial, Liebmann assures us that his second principle is the immediate consequence of recent physiological research, and specifically of Müller’s theory of specific nerve energies. This theory, for which there is allegedly abundant experimental proof, holds that each nerve conducts its specific kind of sensation. The same stimulus striking different nerves has different effects; and different stimuli striking the same nerve have the same effect. This shows, Liebmann concludes, that the content of sensations depends not on the quality of the stimulus but on the nerves by which we perceive it (32). The stimulus for visual perception is like the striking of a piano key, whose action is only the occasion for the content of the perception (the sound), which is completely unlike the stimulus. There is a great disparity between the nature of the stimulus (the oscillation of light or sound waves) and the sensible qualities in the mind (sounds, colours) (57).
After treating the physiological conditions of visual perception in his first chapter, Liebmann proceeds to examine its intellectual conditions in his second chapter. The main problem in understanding visual perception, we are told, is to explain how sensations inside us are perceived as objects outside us. If the content of sensation is only something inside us, a psychic event having no width, length or breadth, why do we perceive it as if it were outside us, a three-dimensional object? “The great mystery of perception,” we are told, “is not how sensations come inside us but how we perceive them as outside us” (66). Liebmann does not claim to have a definitive theory to solve this mystery, though he does attempt to identify the basic mechanism by which it takes place. This mechanism consists in the hypostasization of our sensations, their projection outside our body in the direction of the stimulus of the sensation (70–71). Since this mechanism works subconsciously, we are not aware that the sense qualities are really only our projections, hypostasizations of our own sensations (71). The mind is thus like a laterna magica which projects images inside it as if they were outside it. Just as those images are nothing real but only appear to be so, the same holds for our sensations.
The central thesis of Liebmann’s second chapter is that the motor behind this laterna magica lies primarily in our intellect. The ultimate source of the objective view of the world resides in the concepts of substance and causality, which are universal and necessary principles that govern all sensations. Since these principles are synthetic priori, operating of necessity for everyone alike, they ensure that the content of experience conforms to intersubjective norms. We see the world as something external to us, as something objective, because sensations have to comply with these norms, whose dictates are independent of our will and imagination. What appears independent of our private will and imagination is hypostasized, as if it came from outside us, though it really comes from the necessity of perceiving the world according to these intersubjective norms.
So far, so good. In the third and final chapter of Ueber den objektiven Anblick, however, Liebmann’s argument collapses. This chapter attempts to determine the “transcendent” conditions of psychological perception, just as the first did the sensible and the second the intellectual. But in his effort to spell out these transcendent conditions Liebmann stresses a paradoxical but indisputable conclusion, one that follows of necessity from his basic principles, and one that seems to undermine any psychological interpretation of Kant. The conclusion is this: that the mechanisms by which we perceive the world are themselves only appearances! The brain, the eyes, the nerves. What are they but representations in the psyche of the physiologist? He studies the mechanisms of visual perception, which consist in muscles, nerves and tissues, and treats them as if they were also events in the physical world because they too belong to the human body. But this means that all these mechanisms, like everything else in the spatial phenomenal world, are only so many representations, so many perceptual states, in the mind of the physiologist. Hence these mechanisms cannot really be the ultimate explanans of experience but only part of the explanandum. The explanation of experience now has to ascend to higher transcendent principles, conditions that explain the possibility of all psychological phenomena.
What are these transcendent principles? What are the ultimate conditions of experience?
They are a subject who perceives and an object that causes its perception. The subject alone cannot be the sole condition of its experience, because it does not create its objects, which must be given to it. But as transcendent conditions of experience this subject and object do not fall within experience itself; and so, since all knowledge is limited within experience, they are unknowable. The transcendent conditions of experience turn out to be an unknowable X (the object) and an unknowable Y (the perceiving subject), which somehow interact with one another to make us perceive an objective world (153).
The objection is as obvious as it is inevitable: How can these unknowable transcendent conditions be anything other than things-in-themselves? Willy-nilly, it seems, Liebmann has found himself postulating the very entities he had once denounced. Since the inconsistency is glaring, Liebmann squirms, attempting to deny it to save face. At the close of the third chapter of Ueber den objectiven Anblick he adds a long remark to the effect that his transcendent conditions are not things-in-themselves (155–156). The thing-in-itself is something absurd, a contradictio en adjecto, which, he assures us, his transcendent conditions are not. But this only leaves us with the question why Kant’s things-in-themselves are absurd when, properly understood, they play the same roles as Liebmann’s transcendent conditions of experience? When Liebmann goes on to provide a long description of the attributes of the thing-in-itself—this supposedly unknowable entity—the inconsistency only becomes more embarrassing, because all the attributes he lists are equally attributable to his own transcendent conditions. And so, at the close of Ueber den objectiven Anblick, Liebmann had finally discovered, though he refused to admit it, that the thing-in-itself is not so dispensable after all.
To add one self-inflicted injury upon another, there is another disturbing problem with the argument of Chapter 3 of Liebmann’s treatise. If all the facts of physiology are empirical, presupposing the transcendental conditions of experience, then how are they relevant to transcendental philosophy at all? Liebmann’s treatise was based on the premise that visual psychology is relevant to transcendental philosophy; but his argument in Chapter 3 means that it is utterly irrelevant because these conditions are in principle unknowable. Any attempt to know these conditions through empirical means presupposes them, and so proves to be circular. All the facts of empirical psychology really concern the world as appearance alone, nothing about the conditions that make this appearance possible. This was precisely the kind of argument that Liebmann had invoked against empirical psychology in Kant und die Epigonen. But it was as if he had forgotten it in the first two chapters of Ueber den objectiven Anblick. Although he remembered it in Chapter 3, it was too late to prevent a devastating conclusion: the irrelevance of his entire project, the futile attempt to prove transcendental idealism through physiology.
Yet, as we shall soon see, this was not the end but only the beginning of Liebmann’s travails, his many attempts to unravel the complicated relationship between natural science and transcendental philosophy.
In July 1870 Liebmann’s academic career was abruptly interrupted by a dramatic political event: the advent of the Franco-Prussian war. On July 19 Kaiser Wilhelm I had called upon all the German provinces to unite and to defend the fatherland against “the aggressions” of their traditional foe, France. A wave of patriotic enthusiasm swept through the land in response to the Kaiser’s appeal. Among those who responded was the young Liebmann himself, who later admitted to having been infected with the “furor teutonicus”. He duly enlisted as a volunteer in the Prussian Gardefüsilierregiment. For four months, from September 1870 to January 1871, Liebmann participated in the siege of Paris, sheltering in little villages outside Paris which were under constant French bombardment. After his return to civilian life, he published his memoirs and diaries from these months, which appeared in September 1871 as Vier Monate vor Paris.36
Prima facie it would seem that there is little of philosophical value in Liebmann’s reminiscences. This is indeed the case for most of the book, which is chiefly of historical interest. Still, these four months mark one of the most formative periods of Liebmann’s life, not only morally but also intellectually. There is nothing like the experience of war to collect the mind and to make it think about the meaning of life. Several sections of Liebmann’s tract are filled with general reflections, sometimes in verse, about death, war, peace, history and human nature in general. We cannot ignore these sections, not least because they are the basis of Köhnke’s damning portrait of Liebmann as Heinrich Mann’s Untertan.
There is a remarkable passage from Liebmann’s diary, dated September 24, 1870, where he praises the discipline and esprit du corps of the Prussian Army. Though such discipline might seem ridiculous to an outsider, someone like Heinrich Heine, that would be only a superficial view of its meaning and purpose, Liebmann declares. What reveals itself in such discipline is the spirit of self-sacrifice, devotion to law and the state (30). Egoism is held in check as the individual becomes a working member of the social and political whole. This spirit of obedience and public purpose does not oblige the subject alone, Liebmann is careful to add, but also the Prussian monarch himself, who is only “the first servant of the state” (31). Viewing the Prussian army through a Kantian prism, Liebmann then declares that this ethic of discipline and self-sacrifice is nothing less than “the spirit of the categorical imperative”. Here are the crucial lines:
In this army everything down to the smallest detail and in the greatest extreme is made “exact”, “proper”, [it is] pedantically and painfully prescribed and executed. For an outside observer this might appear as servitude (Kamaschendienst) … But in it is revealed the spirit of discipline and subordination, the postulate of selfless, strict fulfillment of duty, the consciousness of duty to the point of complete self-sacrifice toward law and state. Resistant egoism has to keep silent, and the individual feels himself constantly an obedient member of the whole. Such is the spirit of the categorical imperative. (30)
It was largely on the basis of this passage that Köhnke formed his interpretation of Liebmann. From these lines there seems to speak the true “Prussian lieutenant”, one whose idea of ethics is obedience and subordination to authority. According to Köhnke, Liebmann takes the Prussian military as his model for social order in general, and therefore preaches the complete subordination of the individual to the Prussian state.37 Liebmann’s reference to the categorical imperative in this passage is his idea of “the spirit of the Kantian philosophy”.38 Because he forces Kant’s ethics into this Prussian mould, Köhnke reasons, Liebmann uses Kant’s philosophy to legitimate the authoritarian Prussian state.
Is it fair to interpret Liebmann in this light? Does this passage really represent his general social and political viewpoint? Hardly. One only needs to read further in Liebmann’s text to see the full context and meaning of these lines. There is another remarkable passage where Liebmann records a dialogue between himself and his comrades during Sylvesternacht 1870–71 (238–247). There it becomes clear that Liebmann thinks that the ethic of subordination and obedience is only appropriate in times of war, and then only when the fatherland is in danger. He makes it very clear that it is only as a Prussian soldier that one should live for the state. This life as a soldier is, however, “only for now, only ad hoc”, and it will cease with the peace (244). Like a true liberal, Liebmann then goes on to insist—flatly contrary to Köhnke’s account—that the state is made for the individual, not the individual for the state (245). He looks forward to the end of the war and the return to peace where everyone can follow their own career and go their separate ways.
A closer look at the text also shows that Liebmann does not equate “the spirit of the Kantian philosophy” with the Prussian military ethic. To be sure, Liebmann says that ethic is “the spirit of the categorical imperative”. But there is nothing in Vier Monate vor Paris to suggest that Liebmann read Kant’s philosophy as a whole in such terms. The more modest interpretation, and all that the textual evidence supports, is that Liebmann saw military discipline as one application of the categorical imperative, an application specifically appropriate to times of war. It is noteworthy that when Liebmann later came to write explicitly about “the spirit of the Kantian philosophy” he understood its ethics entirely in terms of moral autonomy, which he explains as taking responsibility for one’s own actions.39 That is hardly the submission to authority that Köhnke sees as the heart of Liebmann’s ethics.
As part of his general portrait of Liebmann, Köhnke stresses his nationalism and chauvinism, especially his contempt for the French and British.40 Here Köhnke is closer to the mark. There can be no doubt about Liebmann’s nationalism, specifically his fervent wish to see Germany united under Prussia. The book has a loving portrait of Kaiser Wilhelm, whom Liebmann sees as the saviour of Germany. The book ends with the enthusiastic declamations: “Lang lebe Kaiser Wilhelm! Deutschland für immer!” There can also be no question about Liebmann’s contempt for the French, whom he would often describe as a rabble, a nation of dishonest, decadent egoists. Yet how extraordinary is such nationalism and chauvinism? It was the common ethos of the age, and we cannot claim that Liebmann’s attitudes are especially extreme or notable. This is duly noted by Köhnke. What he completely fails to mention, however, is Liebmann’s later recantation of his earlier chauvinism in the preface to the second edition of Vier Monate vor Paris. For here Liebmann distances himself from his “blunt and harsh judgments” about the French, which, he confesses, “go beyond the bounds of fairness”. He decided to retain them in the second edition not because they were his persistent convictions but only because of their historical interest, because they revealed something about the common view of the time (iii–iv).
The more serious shortcoming in Köhnke’s portrait, however, is that he completely ignores the other side of Liebmann’s early political philosophy: namely, his pacifism and cosmopolitanism. There are several prominent passages in Vier Monate vor Paris where Liebmann expresses such convictions (184, 240, 246–247, 285). Liebmann was confident that the conclusion of the war would mark a new epoch in history, one more cosmopolitan and peaceful than all the preceding. The age of nationalism was a step forward beyond the dynastic age, just as the dynastic age was a step forward beyond feudalism; but now there will be a new cosmopolitan age that is a step forward beyond the age of nationalism. This new epoch will be “the period of humanity and peace” (240), one that acknowledges “the equal validity of all cultural nations” (247). In this new world order Germany and France will cease to compete with one another and will begin to learn from one another; their virtues will even complement one another to serve as a model of culture in general. What Liebmann admires in Germany is not its peculiar national virtues but its “cosmopolitan sense and its humanist cultural ideals” (285). He believes that it is Germany’s special mission to serve as the motor for this new cosmopolitan and irenic age because its self-interest ultimately lies with peace rather than war. The French cannot perform this role, because they see war as a cause of Gloire et Prestige, and so fail to see how the self-interest of all nations lies in peace (246).
The source of Liebmann’s pacificism and cosmopolitanism are all too Kantian: Kant’s Zum ewigen Frieden, a text which Liebmann cited and knew well (xii, 166). His arguments on behalf of peace come straight out of that Kantian text: that war is becoming too expensive; that war disrupts international commerce; and that the instruments of war are becoming so potent that no one can engage in it without terrible causalities (184).41
How did this cosmopolitanism cohere with Liebmann’s nationalism? Liebmann himself was not so sure. In the preface to the second edition he poses the question, and admits that his own thinking suffers from this common tension (viii). Nationalism is natural and instinctive for human beings, he notes, because it springs from their attachment to their roots and belongs to their very identity. The cosmopolitan man, who is bereft of all national characteristics, is a mere abstraction. If we were to abolish the ties of family, ethnicity, language and nation in favour of some cosmopolitan ideal we would most likely end with the war of all against all (x). Still, Liebmann thinks that nationalism has to co-exist with cosmopolitanism, because it is only in recognizing the equal rights of all nations that we achieve the peace to which all nations aspire.
Seen in context and from a broader historical perspective, Liebmann’s political convictions in Vier Monate vor Paris are those of a conservative liberal rather than a reactionary monarchist. Like many conservative liberals of his day, Liebmann held dear basic liberal ideals—cosmopolitanism, individualism, belief in personal autonomy—but he was also wary of socialism and communism because he was fearful of their levelling tendencies (110–111). If he was sceptical of French republicanism, it was not because he repudiated its democratic ideals, but because he believed, following Montesquieu, that the French people were still not ready for the virtue that a republic required (169). Liebmann shared the general conviction of Weimar culture that Germany’s humanist and cosmopolitan ideals should be a model for all nations. Germany was for him, as it was for Schiller, Goethe and the Romantics, der Kulturstaat, der Land der Dichter und Denker. In the light of later history we can object to these ideals as quixotic and naive; but they are hardly the attitude of a Nazi party functionary. To read Liebmann in that light is a forced and blind anachronism.
A year after his return to civilian life, in 1872, Liebmann became extraordinary professor of philosophy at the University of Straßburg, which was now a German institution after the accession of Alsace-Lorraine to the newly-founded second Reich. Liebmann would remain in Straßburg for the next ten years, starting the tradition that would make the Southwest a centre of neo-Kantianism. Eventually, Windelband, Rickert and Lask would also migrate to Straßburg.
In the 1870s Liebmann continued to investigate the fraught relationship between natural science and transcendental philosophy. Although his first foray into that field, Ueber den objektiven Anblick, had ended in disaster, with him having demonstrated what he intended to refute (the thing-in-itself) and having refuted what he intended to demonstrate (the relevance of physiology for transcendental philosophy), Liebmann pushed on regardless. Well that he did so, for the relationship between natural science and transcendental philosophy is much too complicated, much too amorphous, much too slippery, to be answered with a simple positive or negative verdict about its relevance or irrelevance. The crucial question is how and in what respects it is relevant or irrelevant. The task now was to spell out these respects through more detailed and precise investigations. The product of these efforts was one hefty tome, Zur Analysis der Wirklichkeit, which first appeared in 1876.42
Liebmann’s thinking greatly matured in the early 1870s. The manifest weaknesses of his earlier work taught him the need for caution. Rather than rushing to conclusions and flaunting generalities, Liebmann now realized that it was necessary to proceed piecemeal, investigating topics in detail and in a more neutral and tentative manner, bracketing any preconceived views. His method, as he put it in the ‘Prolegomenon’ to Zur Analysis der Wirklichkeit, would be “analytic”, proceeding from the particular to the general rather than conversely (15–16). Such an analytic method made a general system of philosophy a distant goal, a regulative ideal, which we should strive to approach but which we could never attain.
There can be no question that Zur Analysis der Wirklichkeit is Liebmann’s best work. The book went through four editions, and it was highly regarded since its publication.43 Liebmann considers every major problem of philosophy, penetrates to the core of the issue, and he does so in clear, simple and elegant prose. It is a book from which every philosopher can learn something, even if he or she does not agree with the author’s viewpoint. In its style and method, the careful investigation of concepts and arguments, Liebmann’s book anticipates modern analytic philosophy, though its scope is much broader, indeed so broad that a single worldview emerges from its individual chapters. Wilhelm Windelband wrote of the work: “It is one of the most unique works in which a philosopher ever put forward his worldview. There is, it seems, no trace of a complete picture; each chapter treats its separate problem. . . But whoever looks more closely will find that all these special treatments are parts of an organic whole, that they require and condition one another and present a unified living whole.”44
It is one of the merits of Liebmann’s Zur Analysis der Wirklichkeit that it discusses Kant’s philosophy in relation to the latest results of the natural and mathematical sciences. Not all philosophers could do so. But, originally trained in mathematics and physics, Liebmann was well-equipped to deal with technical questions. Although his discussions are lucid and informed, we must bear in mind that they are also dated, limited by the state of the sciences in the 1870s. Liebmann was writing after the development of neo-Euclidean geometry, the rise of Darwinian theory, and the new psychology of Fechner, Weber and Helmholtz, but also before Einstein’s theory of relativity, which would revolutionize physics in the early 20th century. Still, his essays remain of great historical interest because they show how neo-Kantianism attempted to adapt to and evolve with the empirical sciences.
Three essays in Zur Analysis der Wirklichkeit—‘Phenomenalität des Raumes’, ‘Raumcharakteristik und Raumdeduktion’ and ‘Zur Theorie des Sehens’—are a re-examination of visual psychology, a topic that Liebmann had already treated in his Ueber den objectiven Anblick. Now, though, Liebmann approaches the matter with greater clarity and caution. The question at stake is whether Kant’s thesis of the phenomenality of space has been verified by the empirical sciences. The phenomenality of space means, Liebmann explains, that it has only a “relative” or “conditioned” reality, that is, one that depends on our consciousness and sensibility, such that if they disappear so does space (37). Now does empirical science confirm this thesis? Liebmann is still convinced that it does, rehearsing arguments that he had already advanced in his earlier work. He continues to hold that the theory of specific nerve energies has established that “the quality of sensation is not the quality of the sensed object but a modification of the sensing sensibility” (41). He also still maintains, with Helmholtz, that the general form of space is an intellectual construction, arising from the organization and co-ordination of visual and tactile sensations according to regular laws. “What we see is always optical phenomena, having empirical and not transcendental reality; not only that which we see in space but also visual space itself is projected by our intellect.” (49–50). What is new in these essays is Liebmann’s treatment of the question of how we see the content of our sensations outside us in three-dimensional space (172–186). He now explains in more detail the mechanism by which we project sensations outside ourselves. This projection is an act that locates our sensations in definite places. The process begins when we take ourselves as the centre of our visual world, the axis, as it were, of a co-ordinate system in which we locate all our visual and tactual sensations. We make ourselves, in the simplest case, the vertex of the angle a-C-b, where ‘a’ and ‘b” designate any two distinct sensations and ‘C’ the centre of our visual world. We locate sensations to the left and right of C, so that we can construct a line consisting of the segments a-C and C-b. The addition of these segments into the single line a-C-b gives us the dimension of length. We can do the same for other sensations, say d and f, which are above and below C; we then have the vertical line d-C-f, which gives us the dimension of height. We then do the same for two more sensations g and h, which are before and behind C, so that we get the line g-C-f perpendicular to the other two, which gives us the dimension of depth. By thus locating our sensations in this primitive co-ordinate system we construct a three-dimensional space. A larger space spreads out in wider concentric circles around the original space whose centre is C. Thus space is an intellectual construction, the result of co-ordinating sensations by placing them in particular locations in the direction of their stimulus. This leads Liebmann to the general conclusion: “The space that we see, from our visible body to the stars in heaven, and everything that rests and moves, is nothing absolutely real extra mentem but a phenomenon within our sensible consciousness.” (51)
Two essays in Zur Analysis der Wirklichkeit—‘Subjektive, objektive und absolute Zeit’ and ‘Relative und absolute Bewegung’—consider the classic question of whether space, time and motion are absolute or relative, and end with a qualified defence of Kant’s theory that space and time are absolute. Liebmann maintains a thesis that physicists would now regard as dated: that modern physics presupposes the ideas of absolute space and time. Time cannot be relative, he argues in the first essay, because there are axioms about time—namely, “Time is a continuum”, “Two parts of time are not simultaneous but succeed one another”—that are valid only for an absolute time like Newton’s (105). Space cannot be relative, he explains in the second essay, because, as Newton held, the rotation of a single body in empty space has a motion that takes place in absolute space alone (141). Furthermore, Galileo’s law of inertia presupposes absolute space, because it assumes that a body will move in a straight line, and with a uniform velocity, even when no other body acts upon it (139). It is indeed the case, Liebmann concedes, that any space, time or motion in the empirical world is relative, and that in an empirical regress we will never find any absolute space, time or motion. Still, physics requires the ideas of an absolute space and time for motions that take place independent of other motions (viz. the rotating body, perfect inertia).
The most interesting and original of Liebmann’s essays—‘Raumcharakteristik und Raumdeduktion’—discusses the Kantian theory of space with reference to “meta-geometry”, that is, the new non-Euclidean geometries recently developed by Gauß, Riemann and Lobachevski. Liebmann thinks that non-Euclidean geometry supports rather than refutes Kant’s theory of space (45). According to his interpretation, the new meta-geometry constructs the possibility of spaces of any number of dimensions by seeing them as the product of a co-ordinate system having any number of co-ordinates (58). Just as in analytic geometry we locate a point in Euclidean space with three co-ordinates, so in meta-geometry we can locate a multidimensional space with any number of co-ordinates. Meta-geometry makes Euclidean space simply a special instance of space in general; it holds for a space having three co-ordinates, even surfaces and no curvature. Prima facie this would seem to undermine Kant’s theory of space in the Transcendental Aesthetic, because it shows that Kant’s theory holds not for space as such but only one kind of space, namely, Euclidean space of three dimensions. Liebmann insists, however, that Kant’s analysis is not damaged in the slightest. Kant never said that Euclidean space is the only possible; indeed, he insisted that his analysis of space and time held only for creatures having our human sensibility, and that it is perfectly possible for creatures having different sensibilities to perceive the world according to different spaces.45 In his early 1746 Gedanken von der wahren Schätzung der lebendigen Kräften Kant even imagined that there could be alternative geometries for creatures not limited by our kind of sensibility.46
To clarify the implications of non-Euclidean geometry for Kant’s theory, Liebmann distinguishes between two kinds of necessity: logical necessity, where the opposite of a proposition is contradictory; and intuitive necessity, where the opposite of a proposition is not contradictory but cannot be imagined by us (77). No particular space is logically necessary, such that it alone is the only possible and all other forms of space involve a contradiction. Indeed, meta-geometry shows us that there are as many logically possible forms of space as there are co-ordinates in our system of analytic geometry. Of course, most of these spaces do not exist; yet it is still possible that some of them do, so that there might exist other kinds of spaces beside that of Euclidean geometry. Just because we cannot imagine these spaces does not mean that they do not exist for us. Liebmann warns against the inference non posse videri ad non posse existere (63). He even says that he has discussed the whole matter personally with Helmholtz, who also believed that it is possible for spaces of many dimensions to exist (64). Still, though Euclidean space is only one possible space, the fact remains that it has an intuitive necessity for us. Our intuitions about space are entirely Euclidean, because we cannot imagine any spaces beyond three dimensions. We cannot construct a space where parallel lines intersect, or where two straight lines intersect in more than one point. To this extent, then, Kant is entirely right: our sensibilities work according to Euclidean space, whose axioms and theorems are universal and necessary truths only for beings with sensibilities like ours.
Liebmann summarizes the relationship between Kant’s theory of space and the new meta-geometry along the following lines. The Transcendental Aesthetic consists in three central propositions: 1) that the axioms of Euclidean geometry are not logically necessary; 2) that they are necessary only for a being with a sensibility like our own, that is, they are intuitive necessities or a priori intuitions; and 3) that they are subjective because they are determined by my sensibility alone (77–78). The mathematicians (viz. Gauß and Riemann) accept 1), which is indeed a condition of their postulating the possibility of other geometries. Regarding 2) and 3), however, they have no clear position, because they write as if Euclidean space is only a logical possibility; they leave out of account its intuitive necessity. It is precisely in this later respect, though, that Kant’s theory comes into play. Its central claim is that Euclidean space has an intuitive necessity, a thesis that ultimately rests upon an investigation into human psychology. Liebmann again raises the question why we human beings are so constituted that we perceive a three-dimensional space, though he now admits that his own theory of projection does not completely resolve the mystery and that more research remains to be done (86, 186).
It was altogether fitting that Liebmann, trained in mathematics and physics, should be an apostle for mathematical natural science and a critic of the Naturphilosophie of Goethe, Schelling and Hegel. In the tradition of Fries and Herbart, he deplores the neglect of mathematics in Naturphilosophie and endorses the Kantian dictum that there is only as much science in a discipline as there is mathematics in it. One of the more revealing essays in Zur Analysis der Wirklichkeit—‘Philosophischer Werth der mathematischen Naturwissenschaft’—is a frank and blunt apology for the method of mathematical natural science against that of Naturphilosophie.47 The method of Naturphilosophie is bankrupt, Liebmann argues, not only because concrete conclusions cannot be derived from abstract principles, but also because its qualitative concepts cannot derive or express the exact quantitative ratios of natural laws (280). Precisely because Naturphilosophie neglects mathematics, a vast dimension of nature will be forever inaccessible to it: namely, its quantitative aspect. Nature is a fundamentally quantitative realm, Liebmann insists, where everything has its precise measure and quantity. Although Schelling and Hegel regard this realm as merely accidental or sheer appearance, it is really essential, because what something is, its very individuality, is determined by its precise measure and quantity (279). “Magnitude, to be quantitatively determined, is absolutely everything; and without its quantitative determination everything=zero, i.e., nothingness.” (280; Liebmann’s emphasis). The ideal of natural science is therefore to have “a mathematical theory for all kinds of events in space and time” (281). Liebmann recommends that this ideal replace the metaphysics of Naturphilosophie. Reason in the universe does not consist in spirit, the absolute or the will, but in nothing less than the system of all natural laws (283).
Nevertheless, Liebmann’s mathematical conception of nature and his critique of Naturphilosophie should not lead us to the conclusion that he rejected Naturphilosophie as a whole. The more Liebmann distanced himself from positivism and materialism, the closer he came to the conception of nature characteristic of Goethe’s, Schelling’s and Hegel’s Naturphilosophie. For reasons we shall soon see, the conception of nature as purposive, as forming an organic unity and realizing a rational plan, which is so charateristic of Naturphilosophie, proved to be essential in Liebmann’s battle against materialism. It is now time to take a close look at that battle.
Like so many neo-Kantians, Liebmann formulated his philosophy against the backdrop of the materialism controversy of the 1850s. Materialism was for him the great nemesis, that force for intellectual and moral evil that had motivated him to develop and defend his own Kantian convictions. His concern with materialism, only implicit in Kant und die Epigonen, is evident from the forward to Ueber den objektiven Anblick, where Liebmann complains that there is still no viable strategy against it (ix). Yet it is remarkable that, when it came to providing actual criticisms of materialism, Liebmann held back, saying little or nothing. He was so contemptuous of “Herren Vogt und Consorten” that he declared their ideas “beneath criticism” (144n). Their theories were “Quark”, having been already refuted by the Kritik der reinen Vernunft. Yet it is obvious that Liebmann’s contempt only betrayed his deeper anxiety. The growing power and popularity of materialism had thrown him on the defensive. If he were not to succumb to the very dogmatism he forswore, he would have to do battle against materialism, sooner or later.
Sure enough, Liebmann turned to this task in several essays in Zur Analysis der Wirklichkeit. One of the most substantial of these, ‘Platonismus und Darwinismus’,48 outlines his position on Darwinism, which we will consider in a later chapter.49 Another essay, ‘Gehirn und Geist’, 50 treats the materialist thesis that the mind is identical with, or at least inseparable from, the brain. This thesis had been put forward by Carl Vogt, materialist extraordinaire, who held that the organ for thought is the brain, and who notoriously likened the brain’s production of thought to the kidney’s secretion of urine.51 After having dismissed such a thesis as beneath criticism in the 1860s, it is interesting to find that Liebmann now makes deep and drastic concessions to it in the 1870s. As if to correct himself, he now explicitly declares that the materialist is not to be reproached for holding that consciousness is only an efflorescence of the brain (535). There is so much evidence on behalf of the materialist thesis that the brain is the organ of thought, he now admits, that it is safe to conclude that intelligent activity is a function of brain activity (531). Only someone very partisan and blind (viz. Liebmann in the 1860s) would deny that the brain is “the physical place of individual self-consciousness and all higher mental activities” (532). We should even adopt a kind of “empirical materialism” as our research programme, Liebmann proposes, where we attempt to make exact correlations between sequences of brain events and sequences of thought (536). The motto behind this proposal is a dictum of Lichtenberg: “Materialism is the asymptote of psychology” (536).52
Having made all these concessions to materialism, Liebmann goes no further. He insists that all the facts apparently confirming mind–brain interdependence are ultimately not decisive for our worldview (538). Lichtenberg was wise to say that materialism is the asymptote of psychology, because that means the lines will never reach the curve. For no matter how far we go in correlating brain events with mental ones, there is still the problem of the disparity in kind between them. “What does protein, calcium and phosphorus in the substance of the brain, and the integrity of the two brain hemispheres, have to do with logic?” (540). They have as much to do with one another, Liebmann answers, as the chemical analysis of the water of the ocean with the plans of the sailors who travel across it. He then asks us to imagine the following scenario: our brain research has advanced so far that we can correlate precisely sequences of physical events in the brain with sequences of thoughts in the mind, so that the sequences of brain events “a-b-c-d-e-f” determines exactly the sequence of thoughts “A-B-C-D-E-F” in the mind. Assume that the thought sequence “A-B-C-D-E-F” corresponds with the sentence “I went to the market to buy some wood”. This means that if the brain sequence were in the slightest different, so that it becomes, say, “a-c-b-d-e-f”, it would have to produce a non-sensical thought sequence “A-C-B-D-E-F”, so that the sentence would now become “I went to the wood to buy the market”. But what is the connection between the brain event sequence and logical sequence? Why is it that one sequence makes sense and not the other? There is nothing in the brain sequences themselves that show why one order is logical and not the other. Though Liebmann thinks that finding correlations between brain and thought sequences is entirely possible, and is indeed the goal of all brain research, he insists that such correlations ultimately show the very opposite of what the materialist assumes: that nature has it within its power to produce “an automaton materiale logicum” (561). It is possible to understand this power, and its resulting correlation between brain and thought sequences, Liebmann contends, only if we assume that the brain has been created and organized according to a rational plan in the first place. Thus brain events will produce logical thoughts only because the brain has been created and organized according to logic. Nature cannot produce these thoughts as a blind mechanism but only if it is constructed according to some underlying rational plan (561, 564). As Liebmann summarizes his argument: “If reason is a product of nature, then nature must have reason” (564). Ironically, in drawing this conclusion, Liebmann had come close to the position of Schelling’s Naturphilosophie, whose metaphysics he had just spurned.
It seems that Liebmann, in stressing the rationality underlying nature, had affirmed a teleological conception of nature, according to which nature is created and organized by purposes or ends. This suspicion is duly confirmed by other articles in Zur Analysis der Wirklichkeit. While the teleological conception is only implicit in ‘Gehirn und Geist’, it is more explicit in ‘Aphorismen zur Kosmogonie’,53 where Liebmann argues that there is no conflict between a mechanical and teleological conception of nature. The whole dispute over teleology versus mechanism is obsolete, he argues, because there is no contradiction between them (393). Recently Haeckel has thrown teleology into the dustbin because he assumes it contradicts the mechanical explanation of nature;54 but this only goes to show that he does not know the history of philosophy. One only needs to read Leibniz, Kant and Newton, Liebmann contends, to see that it is possible to combine both paradigms of explanation. There would be indeed a contradiction between teleology and mechanism if one assumes with the old theism that God creates miracles, disrupting the course of nature to realize his ends. But there is no need to accept this antiquated doctrine. We can easily reconcile teleology and mechanism if we understand mechanism as the necessary means for the realization of a cosmic plan (394). The cosmic mechanism must work with necessity, in lawful regular ways, to realize divine ends, just as a machine must do so if it is to realize our ends. Although Liebmann, following Bacon and Descartes, had banished teleology from physics, that is, from the explanation of particular events in nature, he still insisted that it played a crucial role in metaphysics, in the explanation of nature as a whole (396n).
Liebmann’s revival of teleology raises the uncomfortable question of whether he was violating Kantian strictures against metaphysics. In the third Kritik Kant had laid down strict regulative guidelines for teleology, which mandated treating nature only as if it conforms to ends; there is no empirical evidence whatsoever, Kant held, for the assumption that nature really does act purposefully. Liebmann duly notes Kant’s critical doctrine, but only to brush it aside, saying that he will focus instead on the pre-critical Kant, Leibniz and Newton (393). The rationale for this apparently dogmatic move appears only later in another essay, ‘Die Einheit der Natur’,55 where Liebmann addresses head-on the question whether he is transcending the Kantian limits of knowledge in assuming purposes in nature. In this essay Liebmann attempts to provide a rationale for a constitutive use of teleology through a probabilistic argument. He maintains that the probability that the regularities and uniformities in nature arose from mere chance alone is infinitely low, whereas the probability that they came from some common real cause is infinitely high (572). The root of his argument is an analogy: just as Laplace had argued that there is an enormously high probability, namely, four billion to one, that the homogeneity of planetary movements has a common cause, so Liebmann now contends that it is equally probable that the homogeneity of natural laws as a whole must have a common cause. It is left open what this cause must be, but it is clear that Liebmann thinks that it must be purposive, some form of rational design, because the Epicurean hypothesis that it is due only to the chance movement of atoms in the void is highly improbable (573). So, in the end, Liebmann does advocate the constitutive status of teleology, the assumption that the universe is truly guided by ends and that we need not merely treat it (regulatively) as if it were so. In this respect he differs from the lost generation and most neo-Kantians.
Liebmann’s analogical argument seems to violate another Kantian stricture against metaphysics: he is making inferences about the universe as a whole from events within the universe. That kind of inference Kant regards as illicit, and Liebmann himself had affirmed just that teaching in his Kant und die Epigonen.56 Liebmann’s argument seems void, then, by his very own standards.
What defence did Liebmann have for such flagrant hypocrisy? His excuse is surprising, indicating an important shift in his thinking in the late 1870s (574–575). Liebmann fully admits that Kant was completely opposed to such inferences. There is no way that his texts can be twisted to condone them. One half of the first Kritik and one half of the Prolegomena are directed against them. Nevertheless, Liebmann points out that Kant himself has not obeyed his own strictures. In assuming the existence of the thing-in-itself and in making it the cause of experience, he has taken the principle of causality beyond particular events in experience and applied it to experience as a whole. Thus, even though Kant insists that all knowledge is limited to experience, he assumes that the thing-in-itself is the cause of experience. Now comes the bizarre twist in Liebmann’s argument. Since Kant himself has violated his own standards, he asks, why should we comply with them? (575) Why indeed! But with that move, Liebmann had effectively buried his own philosophy of immanence and had given the green light for a new transcendent metaphysics.
Liebmann has sometimes been taken for a “positivist neo-Kantian”57—with some justification. There are indeed positivist strands in his thought. Kant und die Epigonen has its positivist moments, namely, its attack on metaphysics, and its relegation of talk about the transcendent to poetry. Liebmann’s mathematical conception of science, and his critique of Naturphilosophie, also represent a standard positivist position. Last but not least, Liebmann reaffirmed the old positivist dogma that there are only two forms of knowledge: that verifiable by matter of fact, and that demonstrable according to the law of contradiction.
It would be a serious mistake, however, to regard Liebmann as a positivist simpliciter; there are strong reasons for placing him at the very forefront of the neo-Kantian reaction against positivism, which began in the 1880s. With age, Liebmann’s distance from positivism grew. His critique of materialism, as we have seen, had made him more sympathetic towards classical metaphysics. In Zur Analysis der Wirklichkeit he had argued against a completely mechanistic view of mental life, and he had defended substantial forms and the purposiveness of nature.58 While Liebmann stopped short of regarding metaphysics as a science, he still believed that it involved a legitimate aspiration: trying to understand the world and existence as a whole.59 Liebmann had also developed a more critical attitude towards the sciences. Although he stressed the importance of bringing philosophy into alignment with the sciences, he also warned against uncritically accepting their results. The preface to the third edition of Zur Analysis der Wirklichkeit, which was written in March 1900, reveals fully the anti-positivist views that he had nurtured for years. Here we are told that it is a “fundamental mistake” to think that science alone can solve the problems of philosophy. Science is a useful, and indispensable aid to philosophy, but it cannot be its basis. The naturalistic explanation of the world cannot be the complete story, Liebmann assures us, for the simple reason that human beings are not only the product of nature but also its basis.
Liebmann’s evolving anti-positivism is especially apparent from a curious book he published in 1884, his Die Klimax der Theorieen.60 On the face of it this tract is a straightforward epistemological exercise whose business is to distinguish between different kinds of theories about the natural world. There are no explicit polemics in the book, and Liebmann is content to give his main opponent a generic name, namely, “the empiricist”. But as the book unfolds it becomes evident that it is intended as a critique of positivism. Liebmann’s target is most likely to have been the up-and-coming Dozent Richard Avenarius, whose 1876 tract Philosophie als Denken der Welt was something of a positivist manifesto.61 Avenarius wanted to penetrate to the very heart of experience—to experience denuded of all metaphysical presuppositions, which is the basis of all true science. To this end, he announced a programme for “the purification of experience”, which would remove from the given all theoretical accretions and metaphysical baggage.62 Avenarius saw this programme as a completion and correction of Kant: Kant’s critique had determined the a priori components of experience; but it had failed to strip them away and to get down to its raw basic elements.63
Liebmann’s central contention against Avenarius is simple: that if we pursue his purification programme to its end, we get nothing. The idea of a pure experience is a chimera, because experience stripped of the fundamental principles by which we come to interpret and understand it is nothing more than mute and meaningless sensations. Avenarius’ ideal of pure experience forgets one of the fundamental lessons of the Transcendental Deduction of Kant’s first Kritik: that even the given intuitions of sensibility are possible only because of the a priori functions of the understanding. Avenarius underestimates the constitutive role of the concepts of the understanding; it is as if the material of sense were given and as if the concepts of the understanding were only added to them; but a close reading of the Kritik shows that even for that matter to be given, the work of the imagination and understanding must already have come into play. Though it is the inspiration for his argument, Liebmann does not cite this Kantian text against Avenarius. Instead, he lays out his own account of the basic a priori principles of all science, namely, the principles of identity, continuity and causality (78–92). These concepts are not given in experience, or verifiable by it, but they are a necessary condition to make experience intelligible at all. Without them, experience becomes nothing more than a blur of sensations, having neither meaning nor connection.
What is so remarkable about Liebmann’s tract, however, is more its exposition than its argument, which is standard Kantian fare. For most of the book, for six out of seven chapters, Liebmann outlines the different forms of theory, and his account seems to follow along predictable positivist lines. There are three levels of theory, according to Liebmann’s analysis. The first order never leaves experience; its basic principles and concepts are taken from experience, and they derive dependent and secondary facts from basic and primary ones, for example, the theory of wind, which derives air currents from an imbalance in temperature and moisture (18–22). The second order goes beyond the level of experience and explains the phenomena through hypothetical constructs, for example, the atomic theory, or the imponderables of physics (aether, electric fluids) (23–34). The third order is metaphysical. Metaphysics is for Liebmann the attempt to grasp the unconditioned or absolute and to explain everything conditioned and relative on its basis (35–49). As if he were a good positivist, Liebmann states that the ideal for science should be theories of the first order. Such theories should be the basis for all higher attempts at explanation, because only they can be conclusively verified or falsified (22, 54–56).
The positivist reader of the first six chapters of Liebmann’s tract is likely to think that he has found a friend. But the final seventh chapter comes as a rude shock, a surprise punch, a kick in the stomach, for now Liebmann declares that his classification is incorrect, resting on a crude and popular error. We now learn that there really is no such thing as a theory of the first order (107). All theories are ultimately of the second and third orders because they are based on transcendental principles which, as preconditions of experience, cannot be derived from it. The positivist doctrine that scientific theories can be based upon and verified by experience proves illusory, the result of the naive realist assumption that the world is simply given to us.
Besides its critique of the idea of pure experience, Liebmann’s tract contains another important anti-positivist theme: that metaphysics is a perfectly legitimate, indeed necessary, enterprise. The defence of metaphysics in Die Klimax der Theorieen goes beyond that already stated in Zur Analysis der Wirklichkeit. For now Liebmann maintains that metaphysics is a necessity for the programme of the unity of science so loved by positivists. There is a dogmatic metaphysics, which speculates about the unconditioned; but there is also a critical metaphysics, which determines how the various sciences fit together to form a coherent systematic whole (112). Positivism thinks that science stands above metaphysics, which is a lower level in the development of human thinking. But the truth of the matter is that positivism is “an inferior kind of dogmatic metaphysics” because it is uncritical, failing to recognize the presuppositions of its own ideal of pure experience (113).
Liebmann’s understanding of transcendental philosophy gradually evolved in the course of his philosophical development. In the 1860s he had an inconsistent conception of its purpose and logic. On the one hand, he realized that transcendental philosophy is not empirical psychology because its concern lies in determining the conditions of all natural science, including empirical psychology; on the other hand, he continued to see empirical psychology as the basis for transcendental philosophy. In the 1870s, however, Liebmann began to resolve this inconsistency, slowly unravelling the complicated issues concerning the relationship between empirical science and transcendental philosophy. The result was an essentially epistemological conception of transcendental philosophy, one that anticipated the work of Windelband and Rickert.
One of the most important essays for Liebmann’s new understanding of Kant’s transcendental philosophy is his ‘Die Metamorphosen des Apriori’, which appeared in 1876 in the first edition of Zur Analysis der Wirklichkeit.64 Liebmann now explains in more depth the meaning of the a priori in Kant. In Kant und die Epigonen he had chastened G.E. Schulze for having construed the a priori in psychological terms, for having interpreted it as the cause of our representations; but he did not go on to explain how the a priori should be more properly understood. That shortcoming is now addressed. Liebmann first notes how Kant transformed the Leibnizian meaning of the a priori, which made it an innate idea in the soul. Rather than understanding the a priori in such psychological terms, Kant conceived it in essentially epistemological ones, Liebmann contends. The a priori means for Kant the “basic forms and norms of the cognizing subject” (222). These forms and norms are not innate ideas, psychological faculties or dispositions, Liebmann explains, because they have a “metacosmic” dimension, that is, they hold for everything in the cosmos, so that both the subject and object of knowledge fall under them. They govern not only everything we know about nature but also everything we know about ourselves. They are neither subjective nor objective but that which makes the subjective and objective possible. This was a real “revolution in the manner of thinking”, Liebmann says alluding to a famous phrase,65 because Kant turned Leibniz upside down: while Leibniz makes the soul the basis of the a priori, Kant makes the a priori the basis of the subject itself. “Previously it [the a priori] was a psychological apparatus in the head of the earthdweller; now it is extra terrestial, an Atlas that carries on its broad shoulders our entire globus intellectualis” (224). This doctrine that norms and forms have a metacosmic dimension, governing the subject as well as the object of knowledge, Liebmann now regards as the very heart and soul of the critical philosophy (238).
Liebmann is also much clearer in this essay about the distinction between the transcendental and the psychological. The a priori has two meanings in Kant, he tells us (241). There is the metacosmic and the psychological sense. In its metacosmic sense the a priori concerns the basic forms and norms that govern the entire empirical world. In its psychological sense the a priori deals with “the intellectual process in the head of the individual person”. Liebmann thinks that both senses are present in Kant’s philosophy, and that we should acknowledge one as much as the other. The psychological sense is perfectly legitimate, so that it should be possible to talk about the a priori in Leibniz’s terms of “connaisances virtuelles” and “idées innées” (241n). Indeed, Liebmann assures us that he has nothing against even a physiological or “fleshly” interpretation of the a priori, that is, one that talks about it in terms of “dispositions of the brain” along the lines of the theory of evolution (241–242n). Though both forms of the a priori are present in Kant’s philosophy, Liebmann insists they should not be confused. The metacosmic and psychological a priori each follow distinct kinds of laws, which are generically distinct from one another (252). While the metacosmic a priori consists in epistemic, intellectual or “dianological” laws, the psychological a priori consists in natural laws. The epistemic laws are “norms and categorical prescriptions” about how to obtain truth, whereas the psychological laws are natural laws that govern all thought processes, whether true or false (253). In the psychological sense, the distinction between the a priori and the a posteriori is a distinction between the different origins of our ideas, namely, innate versus acquired. In the epistemic sense, it is between different kinds of evidence, namely, universal and necessary versus contingent and particular (240).
Liebmann’s talk about the “metacosmic” significance of Kant’s norms and forms seems to bring him close to objective idealism, according to which such norms and forms subsist by themselves as impersonal laws detached from the knowing subject. He seems on the verge of abandoning his subjectivist principles, given that he now maintains “the basic norms and forms of the intellectual world” are neither subjective nor objective but govern the subjective and objective alike. It then seems to follow that the subject is no longer the source of these norms and forms but only one more appearance or phenomenon governed by them. Yet, in the end, Liebmann resists taking the plunge into objective idealism. He reaffirms his subjectivist principles by insisting that these norms and forms have their source in our “representing and cognizing consciousness” (251). Apparently, though Liebmann is not so explicit, the empirical subject that falls under the norms and forms is very different from the transcendental subject that imposes them.
Liebmann’s final attempt to explain the discourse of transcendental philosophy is his Geist der Transcendentalphilosophie, a short tract which he first published in 1901 but then added to the second volume of his Gedanken und Thatsachen.66 This tract was Liebmann’s final reckoning with the psychological interpretation of Kant, his closing statement of the enduring truths of Kant’s transcendental philosophy. It is not an interpretation of Kant’s texts so much as an argument on behalf of his basic principles. Liebmann is now more explicit and emphatic than ever before that the chief purpose of transcendental philosophy is epistemological rather than psychological. Kant’s central concern, we are told, is to determine “the universal, typical preconditions of knowledge of the world in general” (3), “the ultimate preconditions of all human knowledge in general” (8). While the epistemological and psychological sides stood on an equal footing in ‘Die Metamorphosen des Apriori’, the epistemological is now given priority. It was a mistake of Kant to write about psychology at all, Liebmann now argues, because this deflected from the real meaning and purpose of his philosophy (3, 8–9). What ultimately concerns Kant is not the quaestio facti but the quaestio juris. Psychology deals with the quaestio facti because its concern is to know how as a matter of fact knowledge arises; it wants to know the causes of knowledge. Epistemology, however, deals with the quaestio juris, because it wants to know the evidence or reason for the fundamental principles of our knowledge. It was primarily the quaestio juris that Kant attempted to answer in his transcendental deduction in the first Kritik. These questions are still confused by empiricists, however, because they, like Locke, think we can justify transcendental principles simply by tracing their origins in experience. They fail to see that such principles have a universality and necessity that transcends all possible empirical justification. Even if we were to show that these transcendental principles are not innate at all, it still would not matter for the purpose of their justification. They would still play a fundamental role in knowledge as the preconditions for the possibility of empirical knowledge. Following his previous analysis in his Klimax der Theorieen, Liebmann now understands the a priori simply in terms of the logical status of the most basic principles for knowledge of experience. These basic principles are identity, causality, and continuity of existence and occurrence. Liebmann drops the Kantian term “categories”, probably because of its psychological associations, and calls these principles instead “theoretical interpolation maxims of empirical science”. They are “interpolative” principles in the sense that they add to, or insert something in, experience that is not originally given within it.
Since we cannot justify such principles by the law of contradiction or experience, the problem of their justification still remains. How, then, does Liebmann attempt to justify them? Remarkably, though he clearly poses the question, he does not provide a clear answer to it. Following Windelband, he suggests that the answer to it is ultimately pragmatic.67 The problems of transcendental philosophy are brought into a sharp focus, he proposes, if we formulate them in “teleological” terms, that is, if we ask what are the means for the end to knowledge? (36). The a priori conditions of knowledge are justifiable in these terms, if they prove to be necessary means for the end of attaining knowledge of nature. If, without them, we cannot acquire such knowledge, they have all the justification we need to give them.
In Geist der Transcendentalphilosophie Liebmann reaffirms his conception of the “metacosmic” dimension of transcendental principles, insisting again that they are “indispensable preconditions of the existence of the world” (36). He again resists, however, any move towards objective idealism. These transcendental principles are preconditions for the existence of the world for the subject, whatever it is, and they do not claim to be true of things-in-themselves. Liebmann is now much clearer, however, about the status of the transcendental subject that is the source of these conditions. The “I” of the unity of apperception must be sharply distinguished from our personal and empirical self-consciousness, he insists, because it is the condition for it (29, 34). The “I” can therefore be regarded as “superpersonal” (überpersonlich). This universal and impersonal “I” exists equally in each and every particular and personal “I”, so that when the latter knows its world, it does so through the former which lies deep within it. Adopting a Platonic metaphor, Liebmann describes how each personal and individual self “participates” in the knowledge of the impersonal and universal self just as an ectype participates in its archetype (36). The language again seems to flirt with objective idealism, though Liebmann still resists it, making it clear that it is one subject participating in another.
Liebmann is very firm in these later writings that the ultimate subject of knowledge is unknowable in principle. In ‘Metamorphosen des Apriori’ he states that the subject behind the metacosmic norms and forms is intrinsically unknowable (251). Though we can grasp this subject in its knowing function, it is an unknowable X (252). In Geist der Transcendentalphilosophie he maintains that the “I” that is the knowing subject is never an object, and he forbids the transcendental philosopher to reflect upon it because that would be the worst kind of transcendent metaphysics (35). Though Liebmann does not admit it, this transcendental self is nothing less than that old bugbear he was once so intent on eradicating: the thing-in-itself. It is evident from these passages, however, that Liebmann’s concept of the thing-in-itself had been transformed: it has ceased to be a fiction and has become a reality, though an unknowable one; it now has virtually the same function Kant had assigned it in the first Kritik. Ironically, it was Liebmann who returned to the concept around the very time Cohen and Windelband were so intent on eliminating it.
Liebmann’s defence of metaphysics in his Klimax der Theorieen was the prelude to a metaphysics of his own, his Grundriß der kritischen Metaphysik, which he first published in 1901 as part of his collection Gedanken und Thatsachen.68 It was largely on the basis of this work that Überweg deemed “a tendency toward metaphysics” to be the distinguishing feature of Liebmann’s work within the neo-Kantian movement.69 Yet Liebmann’s turn towards metaphysics was a later development of his thought, appearing only after an inner struggle against the positivist tendencies in his early work. Liebmann’s thinking was moving in a metaphysical direction ever since the first edition of Zur Analysis der Wirklichkeit; he announced a programme for a critical metaphysics in his Ueber Philosophische Tradition, his 1882 inaugural lecture at Jena; but the self-conscious attempt actually to construct a metaphysics appears only in the Grundriß.
Liebmann’s metaphysics was not meant to be, of course, a rehabilitation of post-Kantian idealism, still less of pre-Kantian rationalism. It was to be first and foremost a critical or immanent metaphysics, one that would acknowledge the Kantian limits on knowledge and refrain from speculation about the unconditioned or absolute. To some extent, Liebmann keeps to these self-imposed limits. Throughout the Grundriß he approaches the classical metaphysical questions—the relation of mind and body, of the one and many, of subject and object, of mechanism and teleology—and shows the limits to which they are answerable. Furthermore, he warns against speculation about the ultimate origin of life, consciousness, and the union of mind and body; he insists that the unconditioned is unknowable and refuses to adopt a specific view about its nature; and he constantly advises against drawing hasty metaphysical conclusions from limited scientific evidence. Nevertheless, despite such admirable self-restraint, Liebmann does not always heed his own self-imposed critical guidelines. Towards the classical questions he does not rest content with a simple agnosticism, as if no answer could be given. Rather, he takes a definite stand of his own, defending some of the classical answers. Indeed, in explaining the common source of the lawfulness of nature, Liebmann explicitly endorses speculation that transcends the limits of experience. It has to be said, then, that Liebmann’s speculative practice hardly squares with his critical ideals. Metaphysics, a forbidden fruit, was for him too much of a temptation.
The more one reads through Liebmann’s Grundriß, the more one sees the outlines of a Platonic metaphysics. In classical terms, the Grundriß is a defence of a Platonic worldview against an Epicurean one, that is, it supports a teleological conception of nature against one that would explain everything according to mechanical causes. Liebmann’s “Platonism” (using that term in a broad sense) is really a version of Aristotelianism, one which affirms that forms exist in individual things.70 It is striking, however, that it is not a Kantian Platonism, that is, one which gives the forms only a regulative status; and still less is it a Lotzian Platonism, that is, one which gives the forms validity but not existence. Rather, it gives a constitutive status to the forms, attributing reality or existence to them as the inherent structures and purposes of living things.
Appropriately enough, the Grundriß begins with a spirited defence of metaphysics, which has fallen on such hard times since the rise of positivism. Metaphysics derives from the natural need of human reason to always ask the question ‘Why?’, the urge to push enquiry to its ultimate limits, Liebmann says. That need is perfectly legitimate, and the refusal to permit that question beyond any definite point is the hallmark of dogmatism (92). Like Herbart, Liebmann insists that antinomies inevitably arise in our ordinary ways of thinking about the world—whether the world is finite or infinite?, whether matter is indivisible or infinitely divisible?—and the only means of resolving them is through metaphysics. The positivists pretend that metaphysics is a primitive form of thinking, now made obsolete by the empirical sciences. But the theories of Plato and Aristotle, of Heraclitus and Parmenides, have not been superseded by the sciences; rather, they represent typical or classical answers to fundamental problems (118). The positivists’ attitude towards metaphysics is untenable, Liebmann argues, not least because they have no answers to the antinomies that are inescapable for all human thinking; they either refuse to answer them, or they adopt an answer without having a rationale for it. The positivists have their own naive metaphysics, which they disguise rather than examine. Because of their naivety and dogmatism, they stand not above but below metaphysics in the hierarchy of intellectual development.
Liebmann first considers the classical metaphysical question of the reality of change or becoming.71 This question arises as soon as we reflect upon the classical paradoxes of the infinite, which make change or motion seem unreal because time and space are infinitely divisible. Liebmann insists that we take Zeno’s paradoxes seriously, and he rejects many of the standard solutions to them. Some of the greatest metaphysicians regarded them as unsolvable, and as a result they saw change or becoming as contradictory. Admitting the contradictory status of motion, Parmenides and Herbart denied all reality to the world of becoming, whereas Hegel and Heraclitus accepted its reality but attributed contradiction to it. Liebmann rejects both positions because they rest on a false common premise: that the principle of contradiction is a principle of being rather than thought (121). Things do not contradict one another, only propositions, he insists. Adopting a famous Kantian distinction, Liebmann contends that these positions conflate logical with real opposition, where logical opposition is the contradiction between two propositions and real opposition is the conflict between forces. Accepting that change is a reality, there are two ways of explaining it while still allowing for permanence in nature: the atomistic or mechanical view that there are a plurality of unchanging substances standing in changing interactions with one another; or the Platonic view that everything in the empirical world undergoes change while only their forms or patterns are ideal (123). Liebmann adopts the Platonic view over the mechanistic one on the grounds that everything in nature, even a simple substance, is subject to change. If there is to be permanence at all, then it cannot be within the realm of nature. All that does remain the same in nature are the laws according to which things change (134). The Platonism Liebmann defends here is a modern and revised Aristotelianism. On his reading, the Platonic forms become scientific laws. Although he states that these laws are the expression or manifestation of powers or forces that constantly work within nature, he insists, true to his critical guidelines, that these powers or forces are unknowable for us. We know only the “causa formalis et mathematica” of things, as Newton said, but not their “causa vera”.
It is in treating another classical question of metaphysics—the relationship between mechanism and teleology—that Liebmann’s Platonic metaphysics comes most clearly into focus.72 In the explanation of life, Liebmann argues, we will never be able to dispense with the idea of form. Like everything in nature, organic beings are in ceaseless flux, constantly changing their material constituents, which are always perishing. What remains the same throughout this flux is their form or structure. It is in virtue of this form or structure that we identify living things and regard them as one and the same (143). We attribute, then, a kind of substantial reality to their form or structure, which is what holds together their various elements. This is a kind of Platonism, Liebmann says, which is for him basically “a realism about forms” (144). Although modern evolutionary theory appears to undermine the assumption of substantial forms or unchanging prototypes in nature, we can still reformulate the Platonic theory to show its abiding validity, Liebmann contends. According to this reformulation, the Platonic idea behind a natural kind is the natural law according to which, under the same natural conditions, the same kind of creature will necessarily evolve (145). Hence the theory of evolution does not refute the existence of Platonic ideas but really presupposes them.
Liebmann’s reading of Platonic ideas as natural laws does not reflect entirely the full meaning he gives to them. For he also insists that the Platonic idea should be understood in teleological terms, as the Aristotelian formal-final cause. The idea is not simply the law by which the same organisms evolve under the same conditions—a much too mechanical conception by his own standards—because it is more specifically the inherent purpose or end of the organism. Liebmann argues that, at least for the present state of our knowledge, teleological explanation remains a necessary part of the scientific explanation of life. We still do not know the causal mechanism that led to the birth of life from the primal state of the earth. In addition to all the physical and chemical elements that make up the composition of life, we have to assume something like a “Bildungstrieb”, “Nisus formativus”, or “Lebenskraft” which controls and directs these elements towards ends (161). Liebmann holds, therefore, that teleological explanation is sui generis and irreducible to mechanical explanation. He stresses that the technique of nature to produce its ends is much greater than the technique of man to produce his ends, so that the more intricate organization of nature must proceed from a greater intelligence than man (156).
Liebmann defends teleology against all the traditional objections of Lucretius, Bacon, Descartes and Spinoza.73 He points out, quite correctly, that teleology need not involve committment to physiotheology; he notes that teleology need not be anthropocentric because the concept of inner purposiveness means that an organism is an end in itself and not a means for human ends; and he adds that teleology need not be a refuge of ignorance because its task is not to replace explanation by mechanical causes. All these points are well-taken, though they are hardly sufficient to legitimate teleology on its own terms. Liebmann’s critique of mechanism is at its most topical and controversial when it comes to the Darwinian theory of evolution (163–165). He insists that the basic concepts of Darwin’s theory are still teleological, and belong more to the realm of Aristotle’s metaphysics. Concepts like development, reproduction and the struggle for existence all presuppose that organic beings are purposive (164–165).74
Despite his defence of teleology, Liebmann insists that the complete mechanical explanation of life is an ideal of reason, a goal we should strive to approach even if we cannot attain it (171). He still reassures us, however, that even if this ideal were attained, it would not invalidate teleology, given that teleology and mechanism are still perfectly compatible. The mechanism of nature, the strict working of its causally efficient laws, can still be only a necessary means for the realization of the purposes of things. Just as human artifices must have a mechanism to achieve their end, so organisms in nature must have such a mechanism too (167, 172). But it is at just this point that a gap appears in Liebmann’s defence of teleology. Granted that teleology is still compatible with mechanism, that means only that it is a possible form of explanation. The question remains whether it is a necessary form of explanation. Liebmann thinks that we still need teleology to explain “the inexplicable wonder of organic purposiveness” (172). But that begs the question: What wonder would there be to life if it were fully explicable on mechanical grounds? Liebmann has no definite answer to this question because he vascillates on the crucial issue whether life is in principle inexplicable or whether it so only for the present state of the sciences. There is an anti-mechanist side to him that wants the mystery always to be there; but there is another scientific side that refuses to block the progress of the sciences and recognizes the possibility of an eventual mechanistic explanation of the origins of life.75
Liebmann’s Platonism and anti-mechanism emerge from his treatment of another basic philosophical problem: the relationship between mind and body.76 All the empirical evidence about this relationship seems to confirm, he admits, a “psycho-physical parallelism” according to which all changes in mental states correspond with changes in brain events (187). He stresses, however, that this assumption is only a hypothesis, because we are still far from determining exactly how mental states and brain events correlate with one another (189). We still cannot identify the precise brain event that corresponds to just this thought and no other. But even assuming that we could find a precise correlation between them, Liebmann cautions, this still would not prove materialism, because the correlation is still compatible with other metaphysical systems, viz., Leibniz’s pre-established harmony or Spinoza’s neutral monism, which are no less capable of explaining this correlation than materialism (187, 191). Liebmann’s reservations about psycho-physical parallelism are much greater, however, than his merely warning about its hypothetical status. For it turns out that, on his reckoning, some aspects of mental life will forever remain inexplicable according to this hypothesis. There is no physical analogue, substratum or correlatum, for example, for the unity of the self, which is a precondition of experience and not a datum within it (190, 196–197).
In his ‘Gehirn und Geist’ in Zur Analysis der Wirklichkeit Liebmann was willing to entertain the possibility, at least in principle, that there could be a precise correlation between brain events and mental states. He was ready to concede for the sake of argument that psycho-physical parallelism is correct. Having made that concession, he then contended that the parallelism would only go to show that there is an inherent logic or rationality within nature, such that it could produce something as complicated as a “material thinking machine”. In the Grundriß der Metaphysik, however, Liebmann is not willing to make such concessions. The reason is that he thinks it is impossible for the naturalist or mechanist to ever surmount the dualism between the natural and the normative. While brain events take place according to natural laws, thinking has to conform to normative laws, which differ from one another as much as “is” and “ought”. The normative laws of thinking require intellectual freedom, the possibility that the thinker does not comply with them. If these laws are to be valid, it must be possible for the thinker to act contrary to them; no less than the rules of morality, they require the possibility that one could have done otherwise, that we could have been more careful and vigilant in drawing the right inference (201–202). What brain event could possibly correspond to this hypothetical, indeed counterfactual, possibility?
The transcendent dimension of Liebmann’s metaphysics is most apparent at its close when he treats the classical question of the one and many.77 He raises the question of why there is so much regularity and uniformity within nature. Why are there laws rather than just chaos? The fact that there are so many laws, and that we can unite these laws under even higher ones, indicates that there is probably only a single cause for everything. Liebmann repeats his Laplacean argument in ‘Die Einheit der Natur’ that the probability of a single cause of the regularity or uniformity of nature is overwhelming (217).78 The assumption that there is such a cause seems transcendent because it generalizes from the order within nature to some general cause of nature as a whole (218). Though Liebmann concedes that this is indeed the case, he sees nothing wrong with such a transcendent inference, given that Kant himself made one in assuming that the thing-in-itself is the cause of experience (218). Here Liebmann virtually admits that he will not follow his own guidelines for a completely immanent metaphysics.
Liebmann’s case for having a critical metaphysics is further weakened when it comes to the topic of the source or basis of consciousness. We are duly warned that this source is completely unknowable to us. Since all consciousness, even self-consciousness, involves a distinction between subject and object, knower and known, it is impossible for us to be conscious of the unity that lies at the base of all consciousness, the single source of both subject and object (219). After noting these limits to our knowledge, Liebmann then suggests a way of getting around them: mysticism. Liebmann opens the door for mysticism when he points out that there is “a psychological analogue” for the primal source of the subject and object: dreamless sleep (220). In that state consciousness disappears, so that the subject becomes one with the object; it is as if the subject returns to the source of all consciousness (220). Liebmann then pays homage to the Upanishads and the Vedanta, “whose wisdom has no parallel on earth”, for cultivating a mysticism that would bring us in touch with the ultimate unity at the source of all things (221).
Whatever the value of mysticism, to suggest it as a path around metaphysical limits was scarcely a Kantian attitude. For Kant, the limits of discursive thinking are the limits of all thinking; and mysticism is only a bogus means of avoiding the difficulties of conceptual thought. Nowhere had Liebmann strayed further from the spirit of Kant’s philosophy than in his late flirtation with mysticism. His philosophical development had now run its course, going from one extreme to the other. The man who had once insisted on staying within the bounds of immanence had acquired the urge to transcend them, and through the most desperate means.
1 See, for example, L.W. Beck, ‘Neo-Kantianism’, in The Encyclopedia of Philosophy, ed. Paul Edwards (New York: Macmillan, 1967), V, 468; and Hans-Ludwig Ollig, Der Neukantianismus (Stuttgart: Metzler, 1979), pp. 9–15.
2 Klaus Christian Köhnke, Entstehung und Aufstieg des Neukantianismus: Die deutsche Universitätsphilosophie zwischen Idealismus und Positivismus (Frankfurt: Suhrkamp, 1986), p. 214.
3 Köhnke, Entstehung und Aufstieg, pp. 215–216. The reference is to Der Untertan, a satirical novel by Heinrich Mann, which was published in extracts in Simplicissimus from 1911 to 1914. Its anti-hero, Diedrich Heßling, defers to those above him and brutalizes those below him. After 1945 Heßling has been invariably read as a Nazi prototype.
4 See Section 5, in this chapter.
5 See especially Kant-Studien 15 (1910), which contains many articles devoted to Liebmann. Among the contributors were Windelband, Bauch and Adickes. Volume 17 (1912) of Kant-Studien contains funereal speeches by Bruno Bauch and Rudolf Eucken.
6 In his inaugural address at Jena, Ueber Philosophische Tradition (Straßburg: Trübner, 1883), pp. 5–6, Liebmann paid tribute to his two teachers at Jena.
7 Otto Liebmann, Kant und die Epigonen: Eine kritische Abhandlung (Stuttgart: Carl Schober, 1865). There is also a Kant Gesellschaft Neudruck: Berlin: Reuther & Reichard, 1912, ed. Bruno Bauch. All references in parentheses will be to the original edition, which is cited on the margin of the Kantgesellschaft edition.
8 Duden. Rechtschreibung der deutschen Sprache und der Fremdwörter. 19th edition (Mannheim: Dudenverlag, 1986), I, 244.
9 Bauch, ‘Vorwort des Herausgebers’, p. X.
10 Bauch, ‘Vorwort des Herausgebers’, p. viii. Köhnke, Entstehung und Aufstieg, p. 216, repeats this old view.
11 Köhnke, Entstehung und Aufstieg, pp. 221–222, 228.
12 Köhnke, Entstehung und Aufstieg, p. 218.
13 See Wilhelm Windelband, ‘Otto Liebmanns Philosophie’, Kant-Studien 15 (1910), iii–x; and Bruno Bauch, ‘Nachruf auf den Sarge im Namen der Kant-Gesellschaft gesprochenen Worten’, Kant-Studien 17 (1912), 5–8.
14 Trendelenburg had made his criticisms of Fischer in the 1862 edition of the Logische Untersuchungen (Leipzig: Hirzel, 1862), I, 121–127; and Fischer had responded to them in System der Logik und Metaphysik oder Wissenschaftslehre (Heidelberg: Bestermann, 1865), §§65–66, 77 Zusatz.
15 There is no direct evidence that Liebmann wanted to take part in the brewing controversy. He makes no explicit mention of it. But this might have been because Fischer did not want him to broaden the dispute, which was still limited in 1865.
16 See Kuno Fischer, Logik und Metaphysik oder Wissenschaftslehre (Stuttgart: Scheitlin, 1852), §12, p. 23.
17 As we have seen in Chapter 5, Section 7. Though Kant und die Epigonen appeared in March 1865, half a year before Fischer’s 1865 Logik und Metaphysik, Liebmann would have had many opportunities before then to know of Fischer’s persistent Hegelianism.
18 See Liebmann’s later essay ‘Die Metamorphosen des Apriori’, in Zur Analysis der Wirklichkeit. Eine Erörterung der Grundprobleme der Philosophie (Straßburg: Trübner, 1876), p. 218.
19 Anonymous [G.E. Schulze], Aenesidemus oder über die Fundamente der von dem Herrn Prof. Reinhold in Jena gelieferten Elementar-Philosophie (sine loco: 1792), pp. 296–299.
20 See Liebmann, ‘Vorwort des Herausgebers’ to the Kantgesellschaft edition, p. v.
21 Otto Liebmann, Ueber den individuellen Beweis für die Freiheit des Willens. Ein kritischer Beitrag zur Selbsterkenntniß (Stuttgart: Carl Schober, 1866). All references in parentheses are to this edition.
22 Liebmann, Kant und die Epigonen, pp. 157–203.
23 Liebmann examines two works of Schopenhauer, Die beiden Grundprobleme der Ethik and Band I, Buch IV of Die Welt als Wille und Vorstellung. Here these works will be cited according to Sämtliche Werke, ed. Wolfgang Freiherr von Löhneysen (Stuttgart: Insel, 1968).
24 Schopenhauer, Preisschrift über die Freiheit des Willens, first published in German as the first part of Die beiden Grundprobleme der Ethik (Frankfurt: Hermann, 1841). See Sämtliche Werke III, 481–627.
25 Schopenhauer, Preisschrift, III, 535, 537, 541–542.
26 Since my aim here is to understand Liebmann, I follow his exposition of Schopenhauer rather than Schopenhauer’s own exposition. Whether Schopenhauer is entirely the total determinist Liebmann sees in him is a matter of some debate, not least because Schopenhauer’s position is complex. At §55 of Die Welt als Wille und Vorstellung Schopenhauer contends that our noumenal will is free to create or not create our phenomenal character, and that it can even create a different phenomenal character (I, 396); but he also maintains that the noumenal character, given certain motives, acts of necessity in specific circumstances, and that the appearance it could do otherwise arises only from ignorance (I, 400–401). In general, Schopenhauer defends predestination of all human actions from the original act of will (I, 404), and maintains that only the certainty of the necessity of human actions gives us some solace about them (I, 421).
27 See Schopenhauer, Die Welt als Wille und Vorstellung, §55, I, 404.
28 See Schopenhauer, Die Welt als Wille und Vorstellung, §55, I, 398–399, 402; and Preisschrift, III, 567, 570.
29 See Schopenhauer, Preisschrift, III, 618.
30 Schopenhauer, Die Welt als Wille und Vorstellung §68, I, 514–515; §70, 546–547.
31 Here Liebmann’s criticism is unfair. Schopenhauer does not maintain that we always act in the same way in the same circumstances; he allows for the possibility that, if we acquire new knowledge about our desires and the means to attain our ends, we will act differently. See Schopenhauer, Die Welt als Wille und Vorstellung, §55, I, 405–406; Preisschrift, III, 572. This point is important because it allows Schopenhauer’s subject, despite having a fixed character, to reform its conduct. Schopenhauer holds that, in addition to our noumenal and phenomenal characters, we have “an acquired character”, which arises in the course of experience from greater knowledge of our own individuality, of what we want and how we can get it. See Schopenhauer, Die Welt als Wille und Vorstellung, §55, I, 416–419.
32 See Schopenhauer, Die Welt als Wille und Vorstellung, §55, I, 414–415.
33 Liebmann, ‘Geist der Transcendentalphilosophie’, in Gedanken und Thatsachen: Philosophische Abhandlungen, Aphorismen und Studien (Straßburg: Trübner, 1904), II, 89.
34 Otto Liebmann, Ueber den objectiven Anblick. Eine kritische Abhandlung (Stuttgart: Carl Schober, 1869). All references in parentheses are to this work.
35 Liebmann’s concern with materialism is apparent from the ‘Vorwort’, pp. viii–ix; and the close of Chapter 3, pp. 142–145. His statement that materialism is “unter Kritik” is an attempt to mask how much it really troubles him.
36 Otto Liebmann, Vier Monate vor Paris: 1870–1871. Belagerungstagebuch eines Kriegsfreiwilligen im Gardesfüsilierregiment (Stuttgart: Schober, 1871). A second commemorative edition was published in 1896 by Beck Verlag, Munich. All references here are to the second edition.
37 Köhnke, Entstehung und Aufstieg, p. 223.
38 Köhnke, Entstehung und Aufstieg, pp. 228–229.
39 Otto Liebmann, ‘Geist der Transcendentalphilosophie’, in Gedanken und Thatsachen, II, 73–74, 79.
40 Köhnke, Entstehung und Aufstieg, pp. 216, 224.
41 It is therefore difficult to understand Köhnke’s claim, p. 228, that Liebmann makes no use at all of Kant’s philosophy of history.
42 Otto Liebmann, Zur Analysis der Wirklichkeit. Philosophische Untersuchungen (Straßburg: Trübner, 1876). There were three more editions of this work, in 1880, 1900 and 1911. The 1880 and 1900 editions were enlarged. All citations here are to the third edition of 1900.
43 See, for example, the notice of the first edition in Westermann’s Jahrbuch der Illustrierte Deutsche Monatshefte 43 (October 1877–March 1878), p. 448; and the review of the third edition by Friedrich Steudel in the Protestantische Monatshefte 6 (1902), 413–425.
44 Wilhelm Windelband, ‘Otto Liebmanns Philosophie’, p. v.
45 See KrV A26/B43 and A 42/B 59.
46 Kant, Gedanken von der wahren Schätzung der lebendigen Kräfte, §10, Schriften I, 24.
47 Liebmann, Zur Analysis der Wirklichkeit, pp. 275–308.
48 Liebmann, Zur Analysis der Wirklichkeit, pp. 317–360. We shall also examine this essay in Chapter 11, from a different perspective.
49 See Chapter 11.
50 Liebmann, Zur Analysis der Wirklichkeit, pp. 518–565.
51 Carl Vogt, Physiologische Briefe für Gebildete aller Stände, Zweiter Auflage (Gießen: Ricker, 1854), p. 323. Vogt’s statement goes back to the French materialist Pierre Cabanis, whom Vogt studied with in Paris. See P.J.G. Cabanis, Rapports du Physique et du Moral de l’Homme, in Œuvres complètes de Cabanis (Paris: Bossange, 1823), III, 159.
52 See Georg Christoph Lichtenberg, ‘Einfälle und Bemerkungen’, Heft F 1776–1779, No. 485, in Lichtenbergs Werke in einem Band, ed. Hans Frederici (Berlin: Aufbau, 1982), p. 102.
53 Liebmann, Zur Analysis der Wirklichkeit, pp. 370–414.
54 Liebmann refers to ‘E. Haeckel’s’ “Allgemeine Morphologie”’ but gives no precise citation. He is probably referring to the forward to the first volume of Haeckel’s Generelle Morphologie der Organismen (Berlin: Reimer, 1866) pp. xiii–xv.
55 Liebmann, Zur Analysis der Wirklichkeit, pp. 566–578. This essay first appears in the second edition of the book, which was published in 1880. Since the preface to the first edition is dated October 1875, it must have been written between then and September 1879, the date on the preface to the second edition.
56 Liebmann, Kant und die Epigonen, p. 39.
57 See, for example, Michael Ermath, Wilhelm Dilthey: The Critique of Historical Reason (Chicago: University of Chicago Press, 1978), p. 72.
58 As we shall see in Chapter 11, Section 4.
59 The new attitude towards metaphysics is especially evident in the essay ‘Das ethische Ideal’ in Zur Analysis der Wirklichkeit, pp. 716–722.
60 Otto Liebmann, Die Klimax der Theorieen. Eine Untersuchung aus dem Bereich der allgemeinen Wissenschaftslehre (Straßburg: Trübner, 1884). All references in parentheses are to this edition.
61 Richard Avenarius, Philosophie als Denken der Welt gemäss dem Princip des kleinsten Kraftmasses. Prolegomena zu einer Kritik der Erfahrung (Leipzig: Fues, 1876). This work, as the subtitle indicates, was purely programmatic. Avenarius carried out his programme for a critique of experience in his Kritik der reinen Erfahrung (Leipzig: Fues, 1888–1890), which appeared after Liebmann’s work. The earlier work, though, would have been more than sufficient to make Avenarius’ intentions clear.
62 Avenarius, Philosophie als Denken, §§71–73, pp. 39–40.
63 Avenarius, Philosophie als Denken, p. iv.
64 Liebmann, Zur Analysis der Wirklichkeit, third edition, pp. 208–258. The essay appears in its entirety in the first edition, pp. 191–240. All citations in parentheses are to the third edition.
65 See Kant, KrV, B xviii, where Kant refers to his Copernican view as “die veränderte Methode der Denkungsart”.
66 Otto Liebmann, Geist der Transcendentalphilosophie. Straßburg: Trübner, 1901. Reproduced in Gedanken und Thatsachen, II, 1–90. All references in parentheses are to the later edition.
67 See Chapter 13, Section 5.
68 Otto Liebmann, Grundriß der kritischen Metaphysik, in Gedanken und Thatsachen (Straßburg: Trübner, 1904), II, 91–234. This work should be read in tandem with other essays in Gedanken und Thatsachen, especially ‘Die mechanische Naturerklärung’, I, 46–88, ‘Idee und Entelechie’, I, 89–121, and ‘Gedanken über Natur und Naturerkenntniß’, I, 123–300.
69 Friedrich Überweg, Die deutsche Philosophie des XIX. Jahrhunderts und der Gegenwart, Volume IV of Grundriss der Geschichte der Philosophie (Basel: Schwabe & Co., 1951), IV, 417, 424.
70 Liebmann sometimes uses the term “Platonism” in a generic sense for any theory of the reality of universals. For his account of the difference between Plato and Aristotle, see his ‘Idee und Entelechie’, in Gedanken und Thatsachen, I, 100–104.
71 Liebmann, Grundriß der Metaphysik, pp. 114–139.
72 Liebmann, Grundriß der Metaphysik, pp. 140–172.
73 Liebmann further pursued his critique of mechanism in ‘Die mechanische Naturerklärung’, Gedanken und Thatsachen, I, 46–88; and in ‘Gedanken über Natur und Naturerkenntnis’, Gedanken und Thatsachen, I, 208–230.
74 See also ‘Idee und Entelechie’, Gedanken und Thatsachen I, 113–115.
75 See Liebmann’s ambivalent attitude in ‘Idee und Entelechie’, Gedanken und Thatsachen I, 109–111. Liebmann’s ambivalence reflects an ambivalence he also finds in Kant. See ‘Gedanken über Natur und Naturerkenntniß’, in Gedanken und Thatsachen, I, 248–249.
76 Liebmann, Grundriß der Metaphysik, 172–204.
77 Liebmann, Grundriß der Metaphysik, pp. 204–234.
78 Liebmann, Zur Analysis der Wirklichkeit, 3rd edn, pp. 566–578.