CHAPTER V

SCIENCE AND THE ENLIGHTENMENT

THERE IS A STORY that only once was Newton known to laugh, when someone asked him what use he saw in the Elements of Euclid? But how much more incongruous is the place he has come to occupy in the history of ideas as godfather to the eighteenth-century Enlightenment. For, when one thinks of it baldly, how can the Principia and the Opticks have inspired Jefferson’s proposition that under the law of nature a broken contract authorized Americans to rebel against George III? Or the constitutional device of checks and balances? Or the atomic model of society, individualism in Europe replacing organic feudal corporatism? Or the instinct of Jean Jacques Rousseau that the state of nature is a state of virtue? Or the feeling of romantics that society should be based, therefore, on virtue, and of rationalists that it should be based (on the contrary) on talent? Or the campaign of sly sardonic japing which Parisian skeptics levied against the Christian religion? Or Jeremy Bentham’s vocation as the Newton of legislation, his identification of utility, the greatest-happiness principle, as the social law of gravity, and his gentle determination to make the nations observe it? What, indeed, can Newton, devout and secret man, or his sublime, impersonal science have had to do with any of these humane and public preoccupations of the Enlightenment?

This is no simple question. It immediately raises the disparity between what science is and does, and what people say it is and use it for, between its content and its, exploitation, whether by moral, social, or logical philosophy. The stereotype of rationalism conceiving the Enlightenment on the body of science may be quickly rehearsed. Armed with Newton’s principles, heartened by his success, the philosophes would make over society and culture, in the image of nature, by the use of reason. What did Newton reveal in nature? Harmony, order, things that fit, a world well made. He found cosmic law as an objective fact. What, on the contrary, does the enlightened man observe when he compares society to nature as the Newton-given norm? Conflict, disorder, anachronistic institutions, priests and noblemen who foster ignorant superstition and exploit it for power. Philosophy, therefore, become the science of humanity, will find the principles of order in men and affairs, state these laws of human nature, and a world of reasonable beings will read and conform.

Now, there can be no doubt that the prestige of science derived from Newton’s triumph. The force of the mind seemed equal to the power of nature in the act of understanding. But prestige is one thing. Genuine comprehension is quite another, and on this score the lines begin to blur and run together. The physical science of the eighteenth century could only be Newtonian, of course. But the scientific ideology of the Enlightenment was something less or more. Its authors read their Newton—if, indeed, they always did read him—in the light now of Bacon and again of Descartes. When it was a question of technology and progress, or of descriptive science, optimism was tinged with a certain sentimentality about practical artisans, experiments, and collecting of facts. What chateau lacked its cabinet of natural history?

But the confidence in Baconian classification as the route to knowledge found reinforcement in the Cartesian faith in reason. The most striking illustration is the rapid commitment to just that philosophic mechanism which Newton had expressly repudiated. Newtonian mechanics was universalized in thought, not because of any evidence that the world is nothing but a machine, but because of its rationality. Just so would the Enlightenment bring the Cartesian method from metaphysics to social philosophy (whence, by the way, Descartes had expressly excluded it). Doubt and criticism would purge away obscurity and error. Then reason would rebuild the world of humanity, arming herself with the prestige of science, which we know from Newton cannot err.

Thus the rationalists set about to condemn the structure and institutions of the old Europe as absurd and unjust because contrary to nature. It is not for the historian to complain of the sleight of hand which put this message in the mouth of science. He should only be clear that Newton’s name, elevated now into a symbol, was conjured with in all senses of the verb. The leaders of the Enlightenment practised rational criticism. They adopted the utilitarian idea of progress. And they invested both with the high authority of Newton. Their success testifies to the force of their humanitarian commitment. A liberal is bound to applaud the results. He is bound to approve that movement of thought, radiating from critical France, which carried all the West from the religious and dynastic preoccupations of the seventeenth century, through the Enlightenment and the revolutionary struggle for popular sovereignty, into the democratic preoccupations of the nineteenth century and of our own. Nevertheless, one is equally bound, however liberal, to recognize that the authority which social science (for the thing antedates the name) drew from natural science, was vitiated from the outset by the characteristic determination of social scientists to do good. For Bentham’s relationship to the principle of utility is what Newton’s would have been to the law of gravity, had Newton established that law by persuading the planets to obey the inverse square relationship in their own interest. That is to say, the noble eighteenth-century faith in natural law involved a fundamental confusion between the declarative and the normative senses of law, between “is” and “ought.”

It is best to be explicit about this at the very beginning of a discussion of the eighteenth century when science, no longer simply drawing strength or problems from culture, began to shape the world. Science may be admirable. This book is written in the conviction that it is the distinctive achievement of our history, and that nothing less momentous than the preservation of our culture hangs on understanding its growth and bearing. But the influence of science is not simply comfortable. For neither in public nor in private life can science establish an ethic. It tells what we can do, never what we should. Its absolute incompetence in the realm of values is a necessary consequence of the objective posture. That necessity has never been more narrowly identified than by Henri Poincaré, in an essay of 1913 on “Morality and Science”:

It is not possible to have a scientific ethic, but it is no more possible to have an immoral science. And the reason is simple; it is, how shall I put it? for purely grammatical reasons.

If the premises of a syllogism are both in the indicative, the conclusion will equally be in the indicative. In order for the conclusion to be put in the imperative, it would be necessary for at least one of the premises to be in the imperative. Now, the principles of science, the postulates of geometry, are and can only be in the indicative; experimental truths are also in this same mode, and at the foundations of science there is not, cannot be, anything else. Moreover the most subtle dialectician can juggle with these principles as he wishes, combine them, pile them up one on the other; all that he can derive from them will be in the indicative. He will never obtain a proposition which says: do this, or do not do that; that is to say a proposition which confirms or contradicts ethics.

“Ye shall know the Truth and the Truth will make you free”—it is one of the great themes of the Enlightenment. But for most people emancipation was not enough. It never has been. They are not content to take science for what it is intellectually, a great creation, a description of how the physical world works, beautiful and admirable in itself, but empty of morals and lessons. They want more. They want reassurance about the existence of God from the design of nature, and about His loving care from His continuing to repair its imperfections. They want a license to rugged individualism in the theory of evolution. They want a crumb of comfort about free will in the unpredictability of the electron. They want studies of the mind considered as a digital computer. In short, they want science to give us a world we can fit, as Greek science did, and not just a world like any external object that we can first measure, and then destroy.

In moments of discouragement, therefore, one is tempted to think that the history of the influence of science in culture is bound to be the history of a misunderstanding, in which what changes is the way in which the import of science is misunderstood. But this would be too despairing a view, too priggish an approach, to be adopted by the historian. Whatever else it may be, science is an instrument. It is bound to be used in ways to be judged pragmatically, and not only by their fidelity to the intent of the maker. Science, after all, has no higher claim to innocence than theology or philosophy or literature. It does, however, confront criticism with an essential difference from the other elements of culture. They are about man or God, personality or affairs. Science is about nature. It is about things. And this means that it can scarcely enjoy direct and valid influences as do literary and philosophical schools. So it is that a Marxist regime can permit its physicists but not its writers to receive alien honors. Necessarily, the permeation of culture by science must be a problem in accommodation rather than a study in validity.

The problem is great. Since the eighteenth century, the necessity to work an accommodation for science is what has polarized culture into its two great moods of romanticism and rationalism. Resisting the alienation of nature, seeing Newtonian science only as an impoverishment, the romantic tradition flings out against objectivity, and either declares war against science and all its works, or else (and this continued to be possible right through the nineteenth century) proposes to substitute a subjective science, a science which will fit nature to man by returning from mechanism to organism as the metaphor for order. Nor, though ultimately self-defeating, was this sterile. Biological studies received a tremendous impulse from the romantic attempt to replace physics by biology as the ordering science.

The rationalist tradition, on the other hand, coupled by science with empiricism, proposed rather to accommodate science by fitting man to nature. The instrument was an objectified psychology, which in turn conceived the function of scientific explanation to be a kind of cosmic education of humanity in the order of nature. The most notable scientists of the Enlightenment—as distinct from men of letters and philosophes—participated in this development. Ultimately, it led to positivism, which in its extreme form assimilates all philosophy to the study of scientific method. But before that, its most notable feedback into science itself occurred in the chemical revolution, which styled chemistry into a peculiarly eighteenth-century science.

AMONG the philosophic and literary Newtonians of the French Enlightenment, it is the first and foremost, Voltaire, who comes closest to surviving Poincaré’s criticism. Voltaire explained Newtonian science to the educated public more successfully than any other writer, perhaps because he took more pains to understand it. Nor did Voltaire turn to Newton as to one who had subjected the world to a mechanistic determinism. On the contrary, he turned to Newton as to a liberator, and devoted to physics his best efforts of the 1730’s, the years between his first reputation in belles-lettres and the philosophic crusade, between a deep personal humiliation at the hands of the princely Rohan, and his systematic, life-long vindication of human dignity and civilized intelligence looking out from experience at the world as it was.

“Droit au fait—Let facts prevail,” was Voltaire’s motto. He first became aware of Newton, along with other fruits of liberal thought and practice in England, during his retreat there between 1726 and 1729. He attended Newton’s funeral in Westminster Abbey, and presented the first general sketch of his ideas to the French public in three of his Philosophical Letters of 1734. The balance is held even between Newton and Descartes, but the very existence of rival systems of science suggests the absurdity of dogma. One may choose, but how?

A Frenchman arriving in London finds philosophy changed as well as everything else. He left the world full; he finds it empty. In Paris the universe is composed of vortices of subtle matter; in London there is nothing of the sort. At home it is the pressure of the moon which causes the tides; in England it is the sea which gravitates toward the moon. According to the Cartesians everything happens by virtue of an incomprehensible impulse; according to Newton it is by an attraction of which the cause may not be understood…. Here, then, are ferocious contradictions.

Only later, however, did Voltaire see all the way down the vista opened by Newton. From 1736 until 1741, he and his companion, the Marquise du Châtelet, “immortal Emilie,” delivered themselves over to physics. Her chateau became a learned institute. A laboratory was installed. Researches were put in hand, into chemistry and into fire. Madame du Châtelet translated Newton into the language of Racine, and became an adherent of Leibniz, to Voltaire’s annoyance. With her help he set himself to master Newton by study and correspondence in order to “reduce this giant to the measure of the nincompoops who are my colleagues.” Voltaire’s Elements of the Philosophy of Newton appeared in 1738, a labor of dedication though not, perhaps, of love, or not of love of Newton. Like most people, Voltaire really disliked physics. Nevertheless, it was eminently worth five years of his best efforts and those of his mistress. For however ungrateful the subject, it freed the mind from dogma.

The appeal physics did hold for Voltaire emerges in the very arrangement of his book. It begins—and this is the first of the surprises reserved for those who would trace religious skepticism to science—where the Principia had ended, with the liberty of God to make the world as He, rather than Descartes, had seen fit. But Voltaire was more interested in human liberty. Because of Newtonian science, thought is free, not just of the censor and his fatuities, but free of the more damaging tyranny of metaphysics. About metaphysics Voltaire expressed that scorn on which modern science has acted. For to Voltaire, the externalization of nature was no tragedy of deprivation. On the contrary, it worked a liberation of thought.

Cartesian science, as distinct from the Cartesian critical imperative, had proved amenable to the uses of orthodoxy. Père Malebranche, a devoted and intelligent priest, took upon himself to be the Aquinas of Cartesianism. Cartesian physics was received into the Catholic Church. And there, under the dome of the Sorbonne, the spirit of doubt was laid to rest. Except for that, the theologians perfectly understood Descartes’ a priori manner of thought. They, too, habitually defined doctrine and (human) nature instead of accepting men as they are. And just here lay the distinctive advantage of Newtonian science. Once science became a creation of the mind, instead of a projection of concepts, it could no longer serve as a lens for thought, focusing down onto man as dogma all the necessity inherent in the cosmos.

Voltaire found the humane counterpart to Newton’s physics in the psychology of John Locke. “Just as a skilled anatomist explains the workings of the human body,” he wrote, “so does Locke’s Essay on the Human Understanding give the natural history of consciousness.” And here Voltaire, too, welcomed in empiricism that which wilts presumptuous speculations: “So many philosophers having written the romance of the soul, a sage has arrived who has modestly written its history.”

This (almost universal) coupling of Locke and Newton associated science with liberalism in a nexus of English empiricism. No comfort must be sought therein about science depending on liberal polity. The connection lay in coincidence and circumstance, in history and not in some necessity. Nevertheless, Locke was a loose and seminal thinker, and the coincidence embraced much of the Enlightenment, which was nothing if not eclectic. In politics, the Essay on Civil Government put the case for government by consent on the classic basis of the social contract under natural law. Though written earlier, it was published as justification for the Revolution of 1688, which secured the supremacy of representative assemblies in the world governed by English institutions. The Letter on Toleration is a pragmatic demonstration that civic evils flowed from religious bigotry while profits accrued to the Dutch. The Reasonableness of Christianity, not quite a deist tract, is a lawyer’s brief for a religion cured of zeal by experience. Atheists pretend to be shocked at Jehovah’s vengeful spirit. Locke gave the answer. Condemning all mankind for Adam’s sin was no unjust act, for immortality had been a privilege, not a right, and there is injustice only when rights are transgressed. Such was the temper of Locke’s mind, sensible, moderate, literal, more than a touch philistine, professorial—or rather donnish, for your Oxford don of Locke’s type tends to be a safe man and a bit of a schoolmaster. And what would be the plight of a schoolmaster forbidden by ethics to take away privileges?

The Essay on the Human Understanding develops the proposition that all ideas are records of sensations. Man, accordingly, is what he makes of his experience. That the way to improve him is to give him a better one was the obvious lesson which liberal reformers drew from the sensationalist psychology. Locke based himself on the example of science, which he interpreted as total empiricism. He had no mathematics. Too realistic to try the theorems of the Principia, he asked Huygens whether the geometry was correct. Assured that he might depend upon it, he ignored Huygens’ other reservations and mastered the physical argument and rules of reasoning. In effect, therefore—in this, too, he was prophetic of the Enlightenment—Locke selected from the Newtonian corpus what he could handle.

Going behind Newton, the sensationalist psychology drew inspiration from the whole scientific movement. Locke was a member of the Royal Society in his own right, and a friend of Boyle when Newton was an unknown mathematics don. He had even provided himself with a somewhat ambiguous training in medicine, still the only profession which joined onto natural philosophy. The Essay was jotted down after informal discussions among certain “virtuosi” beginning in 1670. It was published only in 1690, and remained more notebook than treatise. “I will not deny,” Locke disarmingly admitted, “but possibly it might be reduced to a narrower compass than it is: … the way it has been writ in, by catches, and many long intervals of interruption, being apt to cause some repetitions. But to confess the truth, I am now too lazy or too busy to make it shorter.”

The method was “to search out the bounds between Opinion and Knowledge,” for “When we know our own strength, we shall the better know what to undertake with hopes of success.” Immediately Locke confronted that same obstacle which in the Cartesian philosophy had obstructed Newton, the doctrine of innate ideas. If science is introspection, we will never understand nature outside. And lacking those external reference points, neither may we aspire beyond science to its complement, an objective description of how the mind works which creates it. Innate ideas are to be excluded, therefore, in principle and as a condition of method. Every death erases the blackboard of the intellect. Thus, every idea is new, the echo in every life of something heard, something felt, something seen, something touched, something tasted. All the fancies and all the dreams that flutter through consciousness and lodge in thought, all the hopes and all the beliefs we ever hold, the highest theories like the lowest superstitions, all these elements of error and knowledge come to mind from experience.

They come at two levels. Sensation prints direct impressions. But Locke knew that he knew something. The faculty, or rather experience, of reflection comprises a second and higher category of ideas. Through self-knowledge we are aware of thinking, doubting, believing, reasoning, and willing. “This source of ideas every man has wholly within himself, and though it be not sense, as having nothing to do with external objects, yet is it very like it, and might properly be called internal sense.”

This reduction of consciousness to internal perception led Locke’s empiricism toward paradox. For he left the fanning of Baconian optimism about science and progress to successors. He himself pointed rather toward positivism. Only self-knowledge is firsthand and certain. With objects it is even as Newton said. We smell the odors, we taste the flavors, we feel the surfaces, but things themselves we never know. From the very conditions on which science succeeds, therefore, it unexpectedly appears that the proper study of mankind is man. Empiricism walls up truth in humanity, and leaves an educated guess as the best knowledge we can have of nature. In philosophy this skepticism issued in Berkeley’s idealism and Hume’s criticism of causality. But though it is interesting that science introduced skepticism rather than dogmatism into epistemology, the main concern of the history of science is the congruence between Locke’s formulation of the inquiry and Newton’s own conception of scientific explanation. Compare, for example, Newton’s strictures on hypotheses to Locke’s summary on ideas:

My present purpose being only to inquire into the knowledge the mind has of things, by those ideas and appearances, which God has fitted it to receive from them, and how the mind comes by that knowledge, rather than into their causes, or manner of production: I shall not, contrary to the design of this essay, set myself to inquire philosophically into the peculiar constitution of bodies, and the configuration of parts, whereby they have the power to produce in us the ideas of their sensible qualities: I shall not enter any further into that disquisition, it sufficing to my purpose to observe, that gold or saffron has a power to produce in us the idea of yellow, and snow or milk the idea of white, which we can only have by our sight, without examining the texture of the parts of those bodies, or the particular figures or motion of the particles which rebound from them, to cause in us that particular sensation: though when we go beyond the bare ideas in our minds, and would inquire into their causes, we cannot conceive any thing else to be in any sensible object, whereby it produces different ideas in us, but the different bulk, figure, number, texture, and motion of its sensible parts.

Or, as Condillac will say in his lapidary fashion, “Our first object, which we must never lose sight of, is to study the human mind, not to discover its nature, but to know its operations.”

Taking physics as its model, Locke’s science of human nature treated mind on the analogy of Newtonian matter. It was bound, therefore, to become atomistic. Elementary ideas, identical in origin with elementary sensations, made the term of that analysis which would know only operations. These particulate ideas drop into the mind through the five funnels of sense. There they bound, rebound, and combine like the corpuscles of which they are counterparts. In this kinetic theory of the intellect, the association of ideas is the counterpart of the law of universal attraction. And the conception of the mind as an instrument for sorting out discrete impulses becomes, therefore, less novel than the contemporary theorists of communication imagine. For only rarely are technicians correct in their supposition that they were born yesterday.

Will it strain the parallel to carry it one step further? The new psychology followed the new physics in a final respect. It was permitted by a conditional assumption rather than a positive discovery. There was no evidence that all ideas derive from experience, any more than that the texture of matter is atomic. But atomism and—true to the Epicurean prototype—sensationalism allow objectivity. Unless ideas might be related to experience, they would escape exact and scientific study. No science of human nature would then be possible. And that great subject, that closest of subjects, would fall back into the domain of religion and superstition, back to where Jung in fact has taken it, into the collective subconscious whence Freud himself may have emerged rather in word than deed. For if Locke made a fundamental mistake, it was that he over-compensated for antique science in treating objectively a branch of knowledge only to be experienced subjectively.

IT WOULD BE DIFFICULT to exaggerate the eighteenth-century enthusiasm for the proposition that our minds only organize information, messages fed in from experience. Versions of the favorite psychological puzzle were imagined by almost all the famous writers. Voltaire, Berkeley, Condillac, Diderot, all treat the question of how the world appears to a man deprived of one of his senses. Diderot, ever the master of the telling example, pointed to a blind mathematician, one Saunderson, who could conceive geometry to perfection. He had a post at Cambridge. But he had only a partial grasp on the real world. Each sense is a dimension, and he was missing one. The idea of beauty, the idea of duty, even the idea of God, everything is bound to take different shape in the flatland of a man who cannot see.

A real case supported this lesson. In 1728 a Dr. Cheselden of Chelsea Hospital operated successfully for congenital cataracts sealing the eyes of a boy of fourteen. The patient was observed with passionate interest. To the delight of the associationist psychologists, he did not at once understand his eyesight. He had to experience the difference between a cube and a sphere, red and yellow. He thought, said Voltaire—the case figures prominently in the Elements of the Philosophy of Newton—that everything he saw was resting on his eyeballs. For the more fortunate relate touch to vision only by a habit of association which that boy had never formed.

Thus they argued, who would develop the associationist psychology into a school of human nature in the analytical spirit of the abbé de Condillac. Time was, when French science shone in brilliance, that several generations of scientists, led first by d’Alembert and then by Laplace, Condorcet, and Lavoisier, admired Condillac as their authority on method. An intimate of Rousseau and Diderot, and even of the materialist d’Holbach, Condillac was one of the intellectual priests whose scholarship adorned the Enlightenment. Like many philosophes, he was educated by the Jesuits. In Paris he was much invited by the great hostesses, Mlle de l’Espinasse, Mme d’Epinay, Mme de Tencin, in whose salons the commitments of the Enlightenment started wittily as conversation. He kept his priesthood private. The Essay on the Origin of Human Knowledge opens with a passage attributing the occasion for psychology to the fall of man, which deprived us of the divine capacity to know essences. A realistic analysis of the imperfect understanding that survives will permit us to make the most of it. But only there in the preface does Condillac’s vocation intrude into his empiricism.

Condillac took Newton for his model, so he tells us, but went to school to Locke. To turn from master to pupil is a relief. Where Locke was discursive, repetitious, and long, Condillac was incisive, analytical, and brief. “A thing said once, where it ought to be said, is clearer than if repeated here and there, now and again.” There is no mystery about the principles that organize knowledge. They are those that order the correct composition. For Condillac assimilated effective knowledge to communication. Toward this end, he gathered up Locke’s scattered threads of criticism against Cartesian innate ideas and pursued the argument with a truly Cartesian instinct for unity, simplicity, and universality. He took exception, for example, to Locke’s passing remark that, for all we know, God might have conferred the power to think on any odd heap of matter. Condillac is short and severe on this confusion of subject with object: “It suffices to remark that the subject who thinks must be one. Now, some heap of matter is not one; it is a miscellany.”

In such rigorous spirit did Condillac address himself to the difference Locke had admitted between sensation and reflection. “If, as Locke urges, the soul experiences no perception of which it is not conscious, so that an unconscious perception is a contradiction in terms, then perception and consciousness ought to be taken for only a single operation. If the contrary be true, then the two operations are distinct, and it would be in consciousness, and not as I have supposed in perception, that our knowledge originates.” Locke had never faced up to this damaging consequence. Condillac simply abolished the distinction. He described the most advanced actions of the mind without allowing it any initiative of its own. His instrument was an elaborate and a highly original theory of language.

Though not the most inevitable, Condillac’s assimilation of science to language was the most fertile conjunction of empiricism with analytical rationalism in the Enlightenment. The seeds were in Bacon, of course, who had been at his best on the errors imported by words, and on the imperative that names must signify things. But having repudiated abstraction, Baconian natural history could never transcend classification to appreciate the sense in which mathematics is said to be the language of science. Nor, indeed, could this be said with full confidence in its generality before Newton’s procedures were understood. Condillac had those procedures before him, an important advantage for a philosopher of science. He took mathematics, not synthetic geometry (which he thought a siren to tempt the mind into metaphysical chimeras), but rather analytical mathematics, to be the exemplar of language. “Algebra, which is adapted to its purpose in every species of expression, in the most simple, most exact, and best manner possible, is at the same time a language and an analytical method.” Algebra is a set of exact symbols to be manipulated by conventions. By agreement, they always mean the same. No admixture of our own judgment is in them, no adulteration by wishes, no weakening by fears.

On the analogy of the analytical role of mathematics in physics, Condillac would study to sharpen and improve ordinary language as the instinctive analyst of experience. Rude and imperfect though language is, every mental act which we take to be the expression of innate intelligence is in reality an effort at communication. A baby translates every sensation directly into action, cooing and crying, muling and puking. What with observation and training, this uncouth language of action soon gives way to French or English, to conventional signs and symbols. A child who can talk is no longer at the mercy of random events. He can guide himself among realities with a success proportional to his vocabulary, and draw on the common experience and the common wisdom, which are the same thing. The existence of a symbol for what one needs creates the possibility of securing it. Even if all experience is from outside, therefore, to dispose of a language is to be the master of one’s thought. It is to command the instrument which orders the impressions of happenstance into the pattern of civilized existence. The point is to be sure that our words express determinate ideas about things and not figments. Else we err like old philosophers.

Language, then, the conventionalization of symbols from experience, is the cause—in the Newtonian sense in which gravity is both effect and cause, which is to say expression—of the highest and most complex operations of the mind. This was a profound concept, capable of great generality, and highly original. It is odd that it has been so little emphasized in the histories of the Enlightenment, which have preferred to trace to science the vague, ubiquitous preoccupations about deism, naturalism, and social or political reform. Modern literary criticism and modern communications theory sometimes give the impression that they invented the analysis of language, though independently, of course; for one of the findings of that theory, and one of the preoccupations of that criticism, is the isolation which arises from the difficulty of sharing experience. Of that difficulty Condillac was unaware. But surely the assertion is his that “We think only through the medium of words.” It remains a principle of the psychology of art that no dragon, be it never so horrid, can be composed except from the organs of known animals. It remains a curiosity of science fiction that the imagination is dependent on actual scientific dreamings. Do with them what it will, it invents nothing.

After centuries of sophistry and superstition, ordinary language is, unfortunately, a dull and rusty tool. To compare it with the precision instrument of algebra is to confront the difference between science and life. And the main object of rationalism in the Enlightenment was to reduce that difference by right education. Thus it came about that eighteenth-century psychology first built its science of human nature on Newton’s conception of scientific explanation, and then reciprocated by returning to science a conception of method oriented toward education, education taken in the very largest sense of the progressive improvement of the whole of the human understanding.

By the canons of this method, analysis first identifies the elements of a complex subject. These once clear, it ranges and classifies them according to the logical, which is to say the natural, connections that subsist beneath all the welter of phenomena, all the chaos of irrelevant experience. Finally, analysis finds the science its proper language, a systematic nomenclature designed to fix the thing in the name, assimilate the idea consciously to its object, and cement the memory to nature. Thus, to anticipate, salt of Venus becomes copper sulfate. One small stroke of naming destroys a superstition and teaches us a compound.

Indeed, once the nomenclature is established, analysis and naming become a single act, for languages, like algebra, are instruments of analysis, differing only in degrees of precision and self-consciousness. With this procedure, Condillac meant to succeed where Bacon had miscarried for lack of science, and Descartes for lack of humility. He would bring the whole reformation of learning down to a linguistic reform, redesignating words where necessary to make them speak facts, recombining them in a syntax of experience, lending reality to the expression used of the ancient atomists that theirs was an alphabet of nature. “The art of reasoning is nothing more than a language well arranged.” Scientific explanation, then, would consist in resolving a subject into its elements in the objective world, in order that it might be reassembled in the mind by the association of ideas. Thus might the human understanding itself be reassembled in ever closer approximation to the grammar of nature.

This was a philosophy of science well suited to a situation where attention was shifting from the abstract to the experimental and descriptive sciences, from astronomy and theoretical physics to experimental physics, natural history, and chemistry. Newton had carried high theory beyond the capacity of the eighteenth century to do more than formalize the mathematics and perfect the treatment in detail. The humbler sciences, however, did present to method just such a mass of uncoordinated fact as needed ordering by right classification. And in practise Condillac’s favorite analysis came to be less the algebraic resolution of abstract relations of quantity than the simple pigeonholing of the naturalist. For if his inspiration was algebra, his model was botany.

Taxonomy little tempts the historian of scientific ideas. The problems were fussy and practical, but the question whether classifications are natural or artificial did not ultimately prove interesting. In botany the systematics of Carl von Linné prevailed—or Linnaeus, for he universalized his own name in Latin as he did those of plants. Linnaeus held beliefs rather than ideas about nature. He explained the form of species by the most literal and complacent providentialism. This variety of Lapland moss grows just here and not there because God made it to grow here and not there. For “God has suffered me to peep into his secret cabinet.” Nevertheless, Linnaeus was a patient and accurate Swede with the soul of a fundamentalist librarian whose system improved on its many forerunners, beginning with Aristotle’s, in the universal applicability of the criteria.

That plants have sexuality and that flowers (as a rule) are the sexual organs had been established in the seventeenth century. The Linnaean classification took advantage of their form. It distributed plants into twenty-four classes according to the number, proportion, and arrangement of the stamens; each class into orders according to the number of styles; each order into genera according to the method of fructification; and each genus into species by whatever characteristics distinguished it. The system was definite and easy. Rousseau tells how, in his search for consolation, he learned to identify plants in a few weeks, and “All of a sudden, there I was, as much of a naturalist as anyone needs to be who studies nature only to find new reasons for loving her.” Nomenclature was the crux, the binomial system, soon to be extended to zoology, by which the substantive denotes genus and the adjective species. By this means a plant once identified stayed identified. The forget-me-not of England, the oreille-de-souris of France, the Vergissmeinnicht of Germany, become the Myosotis palustris of science, and naturalists of all countries could understand one another.

“These methods,” wrote Condorcet of natural history, “are a kind of real language in which every object is designated by some of its more constant qualities and by means of which, knowing these qualities, we may find the name of the object in the conventional language.” Condorcet was a mathematician, an able mathematician, but at his finest as a statesman of science and a patrician liberal. He expressed an admiration for Condillac’s analysis of method which was shared, not only by the taxonomists whom it helped, but by his colleagues in the mathematical sciences. Retrospect may suggest that it served those sciences less as tool than as reassurance about their human worth. But even so, the fashion of interpretation was one which lent a dignity to the construction of value which scientists put upon their work. This was the first sophisticated conception of method to be drawn from an analysis of science as we still know it. And that makes the comparison with the twentieth century an interesting one. Our own day sees science as action and approximates a proposition to the scientific in the measure that it is operational. It abandons truth as the goal in favor of economy. Not so the forerunners of positivism in the Enlightenment, who saw science as education of the human understanding, and approximated a proposition to the scientific in the measure that it was “analytical” or “philosophical.” Those attributes meant that it lodged in the mind that portion of truth about things which may be found out from their relations and behavior in nature. For the final reward of Condillac’s theory of language was that it redeemed science from Locke’s skepticism about our capacity to know any objective truths. To name is to know, not essences, nor totalities, but what we can know.

Condorcet’s Sketch for a Historical Picture of the Proggress of the Human Mind movingly records that faith in science as the educator of humanity. The essay is a cardinal document of the Enlightenment. By the invention of language man first steps from savagery into community. There the sharing of experience improves upon it. But the machinations of those with selfish interests in ignorance, superstition, and fanaticism artificially prolonged the childhood of the race and kept men dependent on kings, priests, and the philosophers who served them by multiplying ignorance. All history overcomes this ignorance. All history is the curve, almost horizontal for ages but turning now and rising toward the vertical, along which the human mind asymptotically approaches the order—the ordinate to sustain the figure—of nature. History is the education of humanity, then, as science is the educator:

If one studies this development as it manifests itself in the inhabitants of a certain area at a certain period of time and then traces it on from generation to generation, one has the picture of the progress of the human mind. This progress is subject to the came general laws that can be observed in the development of the faculties of the individual, and it is indeed no more than the sum of that development realized in a large number of individuals joined together in society.

Moreover, now that science has found its method, there is no limit to the perfectibility of man. For, “All errors in politics and morals are based on philosophical errors, and these in turn are connected with scientific errors. There is not a religious system nor a supernatural extravagance that is not founded on ignorance of the laws of nature.”

Nor was this a faith without works. It was in the Enlightenment that technology first began to feel that rationalizing touch of science which in more recent times has transformed the world. The historian may at first be somewhat puzzled by the contemporary testimony to the renovation that science was bringing to industry. For there is very little of science in the complex of technological innovations which made the industrial revolution. Deep plowing and crop rotation, smelting with coke, the spinning jenny and water frame and cotton factory, the puddling process for the conversion of iron, even the improvement of the steam engine by the separate condenser and the sun-and-planet linkage—these owe nothing to the contemporary achievements of basic science, to taxonomy in natural history, to the theory of combustion, to the foundation of metrical crystallography, to the discovery of the electric current, to the extension of the inverse square relationship to magnetic and electrostatic forces, to the formulation of analytical mechanics by Lagrange, or to the resolution of the planetary inequalities and the vindication of Newton by Laplace.

Clearly theoretical science had very little to offer industry in the eighteenth century. What was applied was scientific method. When scientists turned to industry, it was to describe the trades, to study the processes, and to classify the principles. Diderot’s Encyclopedia, so much the most famous venture of the Enlightenment that the words “Encyclopedist” and “philosophe” became almost inter changeable, was itself a natural history of industry. Its subtitle was “Analytical Dictionary of the Sciences, Arts and Trades.” In Diderot’s definition a good dictionary should have “the character of changing the general way of thinking.” Through extraordinary vicissitudes with the censor, the seventeen volumes appeared before the subscribers in the complementary guises of ideology and technology.

Diderot’s masterstroke was to make the technology carry the ideology. It is the latter which has naturally enough monopolized the attention of intellectual historians, for it is the ideology of progress and liberalism which, conceived in the flirtation of the French Enlightenment with Locke and the English Constitution, burst passionately into life in the French Revolution and matured into the verities of modern democratic government. But the articles on politics and religion had to present all this indirectly, in a vein of innuendo and irony. Sarcasm disturbs and wounds and is never popular, even when justified. At the time, therefore, it was not the liberalism of the Encyclopedia which was popular. It was the technology, taking seriously the way people made things and got their livings, dignifying common pursuits by the attention of science.

For the Encyclopedia, and with it a multitude of industrial studies by the foremost scientists of the Academy, were attempts, Baconian in inspiration but informed by sophisticated method, to lift the arts and trades out of the slough of ignorant tradition and by rational description and classification to find them their rightful place in the great unity of human knowledge. The metal industries, to take an example, were not at first much changed by the development of metallurgy. They simply began to be understood. But that processes will be altered for the better if their principles are understood, that artisans will improve their manipulations if they know the reasons for them, are illustrations of the faith in progress through classification, industrial examples of the belief in scientific enlightenment as a kind of cosmic education. As a result, it was less often necessary to complain of the obstruction of rational procedures by the ignorance and traditionalism of the artisan. Popular superstition was always the dragon for the rational critic to slay, and whether he looked to religion or to technology, he found it flourishing in ignorance and secrecy. And this movement of publicity conjures up the contrast between the enterprising manufacturer of the nineteenth century, the bold engineer, on the one hand, and on the other, the Gothic master-craftsman of olden times, protecting his secrets and his mysteries, bending over his cauldron and stirring some traditional receipt, some confidential brew. “To the tableau of the sciences,” writes Condorcet, “must be joined that of the arts, which leaning on the sciences, have made great strides and broken the bonds of routine.”

It vindicates the reality of ideas to find them embodied in institutions. A tragedy attended Condorcet’s faith in science and reason. He wrote in hiding from the guillotine. Nor did he survive the Jacobin Terror of the Revolution, which struck down, too, the scientific institutions of France, partly as survivals of the old regime, partly, too, in a fit of vulgar, sentimental petulance against the hauteur of abstract science, the impersonal tyranny of mathematics, the superiority of the scientist over the artisan. But liquidation was only one aspect of science in the Revolution. For the views of Condillac and Condorcet came into their own after the fall of Robespierre, when the rationalist tradition of the Enlightenment was institutionalized in the educational foundations of the French Republic.

Upon the tabula rasa left by the Jacobins, the Directory erected a new set of scientific institutions: the first École normale, the Ecole polytechnique, new medical faculties in Paris, Strasbourg, and Montpellier, the Conservatoire des arts et métiers. Only the Muséum d’histoire naturelle emerged flourishing from the Terror, favored by the romantic enthusiasm for botany and Rousseau’s nature. Other schools were revived, the École des mines, the École des ponts et chaussées, the Collège de France. Finally, at the summit was created the Institut de France. Thus, France was endowed at one stroke with her scientific institutions, and the first generation who taught and studied in them assured the restoration of her scientific leadership and its enlargement in the early nineteenth century.

It was a remarkable effort, animated by a consistent philosophy, which was nothing less than to unify the sciences through a common conception of scientific method, and in so doing to link them both institutionally and philosophically to realizing the idea of progress. So for a time, science was organized as a function of its educational mission. Polytechnique assembled the first scientific faculty, as distinguished a faculty, man for man, as has ever existed. For the first time, students were offered systematic technical instruction, directed toward engineering to be sure, but under the foremost men. The students, able and eager, chosen by competition, were immensely exhilarated by the sense of being conducted at once to the very forefront of scientific conquest, and being told that the future of the Republic, which was to say mankind, depended on how they acquitted themselves in so exposed a situation.

But Polytechnique had an equal influence on its teachers. If one were to read only the research memoirs of the Institute in its first ten years after 1795, one would conclude that French science had collapsed with its Academy. Quite erroneously, for the explanation is that scientists were communicating, not primarily with their colleagues, but with their students. Polytechnique made scientists into professors—again for the first time. It brought Lagrange back to mathematics from a preoccupation which had enveloped him since completing the Analytical Mechanics ten years before. Monge drew descriptive geometry together for his course. So, too, did Laplace come to write the System of the World and the Essay on Probability. Cuvier’s Lessons on Comparative Anatomy were given at the Collège de France. Lamarck first presented the idea of evolution as the framework for his lectures at the Museum of Natural History. In short, the systematic treatise displaced the research memoir for a time.

This necessity to reorganize for teaching intervened in the philosophy of science between the Enlightenment and positivism, introducing a displacement toward action, a great enrichment of detail, and a certain access of rigor. It involved the scientists themselves in the preoccupation with method, with classification, with nomenclature. The author of a treatise, at once investigator and professor, would address himself to his entire science. This he would expound according to whatever principles resolved it into a rational body of knowledge. He would present them, not just as an authority, but argumentatively, as an advocate. His claim to originality lay, less in this or that discovery, than in having discerned the principles. So Cuvier founded comparative anatomy in the principle of the subordination of parts. So Monge gave credit to Linnaeus for his idea of grouping surfaces into families. So Bichat brought anatomy to the instruction of physiology by founding histology in the classification of tissues. So Berthollet looked to statics for the idea of chemical masses in equilibrium.

The force and range of the work were remarkable, then. It would be no exaggeration to call this French essay in rationalization the last thrust of the Enlightenment, by which the Enlightenment returned whence it had originated and repaid the debt it had incurred to scientific culture in the time of Voltaire. A unity was imparted to scientific effort which it was not to know again. No doubt the universality of analytic method rested on just the kind of semantic illusion which that method set itself against. What is an algebraic process in Lagrange remains simple taxonomy in Linnaeus. But the difficulty was concealed by a very worthy commitment to that kind of tolerance and mutual respect which rescues communication from specialization by means of the comparative method. For as a matter of principle, no one of these French savants limited his vision by his science: “It is certainly,” wrote Cabanis, who founded his moral philosophy in physiology, “a magnificent and beautiful conception, to consider all the arts and all the sciences as forming a community, an indivisible whole, limbs from the same great trunk, united by a common origin, and still more by the fruit they are destined to bear: the progress and happiness of mankind.”

MEANWHILE, what of romanticism? That Protean mood, as everyone knows, occupied the side opposite reason on the coin of the Enlightenment. But definitions have led armies of scholars through Serbonian bogs into dumps of Ajalon. How evident it is that Burke and Shelley are both romantics, yet one is the apostle of aristocracy and the other of humanity. Similar ambiguities couple Blake with Carlyle, Buonarotti with Maistre, Schelling with Fichte. Always a seer, Coleridge observed the French Revolution first through the enthusiastic eyes of radicalism, and then, passing a hand before his gaze, through the horror-struck eyes of reaction. Which is the true romantic, Napoleon or Robespierre, the eagle or the doctrinaire? Such questions are not to be answered by multiplying examples. And it may be that the difficulty of going beyond this in the histories of politics, philosophy, and literature, is that those areas of expression contain only the fruits of romanticism. Its roots go deeper into man’s consciousness of nature. Perhaps, therefore, it is the history of science which will permit us to be explicit, dealing as it does with ideas about nature. These are ideas about which it is possible to be definite precisely because they are about things instead of values. Moreover, the general problem presents itself to the historian of science in an inescapable particular case, that of the greatest of all romantic minds. What is to be said of Goethe as a scientific thinker? And as a man of the Enlightenment?

For on the one hand, Goethe made an undeniable discovery in comparative anatomy, the intermaxillary bone in man. His studies of the metamorphosis of plants were meant seriously, and have been taken seriously by biologists. On the other hand, his polemic against Newton, going beyond the theory of colors to Newton’s entire philosophy of nature, appears a dismaying anachronism, not only in itself, but in coming at the end of that century supposed to have been inspired by the Newtonian spirit, and on the part of one taken to be the quintessence of enlightenment, or at least of Aufklärung. “As for what I have done as a poet,” he said to Eckerman in 1829, shortly before he died, “I take no pride in it whatever. Excellent poets have lived at the same time as myself; greater poets have lived before me; and others will come afterward. But that I am the only person in my century who knows the truth in the difficult science of colors—of that, I admit, I am not a little proud, and here I am conscious of superiority to others.”

Nor will we find the clue to an interpretation in the rebellion of Jean Jacques Rousseau against the Encyclopedic spirit. We must look for the origins of romanticism into experiences more cosmic than that hot walk to Vincennes in the summer of 1749, when Rousseau, glancing through the Mercure de France on his dusty way to comfort the imprisoned Diderot, came upon the essay question set by the Academy of Dijon: “Has the progress of the sciences and arts done more to corrupt morals or improve them?”—and arrived “in a state of agitation bordering on delirium,” self-converted to his crusade against the cultivated intelligence. With Goethe we are concerned with something more serious than the heart turning against the head. He is not simply enlarging Rousseau’s revolt against Voltaire into a counter-revolution against Voltaire’s master, Newton. For one thing, Rousseau was not himself systematically hostile to the spirit of objective science in the eighteenth century. His was rather the sporadic petulance of the paranoid than the vision, or the memory, of some more grateful science. It is significant, for example, that Rousseau as amateur botanist welcomed Linnaean technique in taxonomy. With all his touchiness in personal matters, it never offended him to range the specific productions of nature into fixed categories of form. Not so casual was Goethe, whom that process insulted deeply.

To appreciate the burden of that insult, it is Rousseau’s involuntary host whom we must study, Denis Diderot, a spirit as various in expression as romanticism itself, and with Condillac perhaps the most significant of the philosophes. Nor need this prove confusing if we do not insist on assigning every figure and every venture categorically to rationalism or romanticism, but let them rather participate in each in some appropriate measure. Thus, for example, through Diderot’s Encyclopedia, a work, certainly, of rationalism and positive method, run those counter-connotations of populism and sentimentality, secularized echoes of the Christian assertion of the dignity of labor, which assign humility and truth to common pursuits, to technology and not to science, and which in the manner of Bacon flatter the artisan that he is the one who knows in practice what the scientist obscures by theory. So it is throughout Diderot’s writings. Each served as a vehicle in praise of some aspect of the natural man. Nor must we look for any more superficial consistency. Diderot cannot be assigned to either the rationalist or the romantic moods. He belonged to both and to neither. Intelligent, amorous, sensuous, cultivated, critical, sentimental, humane, hard-working, humorous—he was in his own eyes above all else virtuous, in that his life and writings affirmed the innocence of nature, of nature in general, of his own nature in particular, and of the opportunities afforded by their congruence.

“The distinction,” wrote Diderot of the picaresque title character in Jacques the Fatalist, “between a physical and a moral world seemed to him empty of meaning.” That remark contains a theme. It is the theme of Diderot’s natural philosophy. More than that, it is the basic theme of romanticism, composed by Diderot in the Enlightenment when modern science first confronted culture. For the romantic response to physics in the Enlightenment is perhaps the most important expression of the tension which must exist between science and the aspirations of humanity to participate morally and through consciousness in the cosmic process. Those aspirations require a nature different from that described by post-Galilean science—not the nature of atomism, where science observes motion and measures quantity; nor even the nature of the Aristotelians, where science classifies forms and defines goals; but rather the nature of the Stoics, where science discerns activity, where its object is virtue rising out of nature, and where cosmic personality is the source of order.

Newton’s world offered virtue no purchase. And just as in Hellenistic times, when the Stoics spoke for the dynamic unity of nature against the Epicurean death-sentence of atoms-and-the-void, so the romantics of the Enlightenment seem to have recalled as against the Newtonian “corpuscular philosophy” that ancient retort upon atomizing kinetics. It is probable that the eighteenth century knew the school through the Roman Stoics, and particularly Seneca, whose emphasis on civic virtue and duty appealed to its high sense of res publica. Senator and patrician, Montesquieu breathed stoicism into the Spirit of the Laws. And before considering Diderot’s philosophy of nature, it may be worthwhile to recall, for a moment, the main notes struck by this last of the Greek schools to inform the consciousness of nature which we have inherited, clothed in science, and transformed here in our own world of the West.

The concepts of that school had descended from the prehistoric representations of natural forces preserved in myth and legend. Stoic physics was an attempt to elevate this legacy into science and philosophy, and to combine it with the cosmology of Heraclitus, seeing the world as flux and fire, conflagration and return. For the Stoics it is always the activity, and not the matter, in things which has ontological significance. And the principle of activity in the cosmos, what tenses it into unity, is the breath of the spirit—pneuma, which ties the world into one dynamic whole, which does for the world what life does for the animal, and which, therefore, is the life of the world. Strictly speaking, however, we can never say what pneuma is. Stoic metaphysics treats of becoming, not of being. Stoic logic puts reason in the verb, not the substantive. We can only say what pneuma does. And what it does is, first of all, to bind together substances which would otherwise be passive, undifferentiated stuff, to lend them permanence and stability. It acts as the erethitic agent in matter, which it permeates as a sexual stimulus penetrates erectile tissue in animals. It is the flex in the muscle, the stretch in the rubber band. But in order to create unity in nature, pneuma has to abandon simplicity for itself. Not only does it bind, it differentiates. Those properties of bodies which the Epicureans attributed to the shape and arrangement of atoms, the Stoics read back to its state of permeation by pneuma. For them there are no boundaries in nature. Combination can never arise from juxtaposition, but only from the blending of principles, intimately melting into that perfect union which lies beyond junction in identity. And change is a metamorphosis throughout the whole. A simple rearrangement of the parts is, indeed, no change at all.

The Stoic world, in short, is a dynamic continuum where causality reigns hand in hand with sympathy. Strict causality is implicit in the unity of nature. In Stoic doctrine it assumes the guise of destiny or fate. And this permitted the reconciliation, or the identification (for the Stoic drive is always integral) of causality with Providence—not a capricious Providence like that into which the conflict of subordinate Aristotelian purposes might too easily degenerate (and in Christian natural theology did degenerate), but a lofty Providence which knows its own mind utterly. Perception, in this doctrine, is penetration of the senses by the real qualities that run through things—participation, therefore, of consciousness in the flux and process of the world’s great life. By the same token, knowledge is illumination of the soul by the truth in nature, by the truth and by the good. But there is withal a democratic implication, more subtle in its appeal to the Enlightenment, perhaps, than hard lessons of civic virtue, but more popular, too, and much easier. For it is the common understanding which holds the truth. The sage is teacher, not researcher, who discerns the notions common to all men, lays down rules of conduct from nature, and finds the correspondences and sympathies between cosmos and personality, the great world and the little.

THE FIRST THRUST back from the eighteenth century to this more intimate sense of nature came from chemistry, in an attempt to deepen the concept of matter, to restore body to what physics deprives of every attribute but location and dimension. This, it must at once be said, was not our sort of chemistry, not the recognizable chemistry with which we will be concerned in discussing Lavoisier and Priestley. Rather was it an operational mode of communion with nature, an archaic, sympathetic chemistry addressed to a notion of the physical now quite forgotten, and so far as science is concerned, quite rightly forgotten. For in speaking of physics as concerned with bodies in motion, we forget that the word “body” originally implied organization, internal material organization, with which chemistry might as properly concern itself as biology. Indeed more properly—the word “biology” had yet to be invented, and the concept of organism thereby confined to that which lives as an individual instead of as a world.

The article on chemistry in Diderot’s Encyclopedia is extremely curious. It is by Venel. He invokes a new Paracelsus, who will make chemistry the science that understands nature and displaces geometry from that pretension. He will be gifted, this neo-Paracelsus, with the sheer technical insight to penetrate beyond physics. But he will have a spirit like the pre-Newtonian philosophers. They “saw nature better as it is,” because “a sympathy, a correspondence was only a phenomenon for them, while for us it is a paradox as soon as we fail to bring it down to our pretended laws of motion.” Physics, to pursue the comparison, is superficial. Chemistry is profound. Physics measures the gross, external characteristics of bodies. Chemistry penetrates their essence. Physics confounds abstractions with truths. One asks for a fact. It replies with a theorem. The physicist calculates in rigor to arrive at those exact theories, which experiments then confirm—“approximately.” The chemist never deludes himself by calculation. He apprehends his theories rather by an “experimental instinct.” In his case it is the theory which is approximate. But as the reward of his humility, the fit with nature is exact.

The question, then, is nothing less than the structure of being in nature. Mechanics will never bear the chemist into the heart of things, for the texture of reality is not corpuscular. And the essential merit of chemistry is that it takes the sting out of atomism. For it allows the masses in which atomism resides no ontological interest. Thus chemistry provides the empirical way out of Newton’s unreal abstractions. The qualities in things are what impress our senses, our windows on reality, and this reality inheres, not in mass, but in the principles which run through the world as activities, as bearers of quality and agents of perceived effects. The physicist, therefore, who denies existence to entities like yellowness and life and fire is simply presumptuous. They do not fall in his field.

It is not for the physicist to study quality, nor for the chemist to study quantity. Venel dismisses Boyle as a physicist. The chemist’s operations will be different. His laboratory will offer no scene of weighing and measuring. The combinations and separations of matter are what concern him in its state of interpenetration, and masses do not combine. They only aggregate. Principles are what combine, and the chemist, therefore, will catch glimpses of “the life of nature” coursing through his laboratory in phenomena which run all through, around, and under mass: in effervescences and distillations, evaporations and condensations, rarefactions and expansions, elasticity, ductility, malleability, and fluidity. The image is of stretchings and blendings in depth, rich with the Faustian sense that nature has an inside. There is nothing transcendental about it. Nor is it the chemistry of a spiritual world. Rather, it is the chemistry of a world alive. Venel is always moving in the mind’s eye from fermentations in his laboratory through digestions in the animal, deep into the mineral gestations of the earth, whose cosmic womb is the home of unity in nature. And in his laboratory, your chemist is almost Hippocratic. He wields his implements with art. His hands are gentle. It is the physicist who brutally pulverizes, ignites, and destroys. The chemist does not analyze. He divines.

The chemist’s world, then, is a palpable continuum. His science is Cartesianism stripped of geometry with its clear ideas. To replenish the Newtonian destitution of nature, it sees down into a world pulsing with activity. In place of universal attraction between particles, Venel has discovered that the fundamental property of matter is universal miscibility. But chemistry is more than intimacy with nature. It has the common touch. It is everybody’s science, the poor man’s manual metaphysics, whereby that artisan in whose skills true wisdom lies manipulates reality, not in the humiliating abstractions of mathematics, but with his own hands: “Chemistry speaks a dual language, the popular and the scientific.” And all this seems harmless enough, until suddenly, out of the Encyclopedia, comes in one startling sentence the authentic voice of vulgarity. “Parlez plus bas,” the mathematical physicist is told, “Pipe down! A coal heaver would die laughing if he heard you.”

In Thoughts on the Interpretation of Nature, Diderot alludes to this science of the chemists as one example to be emulated in handling nature with the surety of experimental art. But sentience and organism weave a more grateful veil, and though Diderot drew his conception of palpable reality from the continuum of activity, he transposed it out of chemistry into the far more plausible terms of natural history, launched it in the flow of time, and created that idealistic outlook which dominated much biological thinking until the import of Darwinism was fully appreciated, which is to say until very recently. The opening paragraphs of that essay prophesy the imminent decline of mathematics. It is an observation which has been frequently forgiven as the momentary enthusiasm of one who would restore ordinary sight to eyes dazzled by the glamor of Newtonianism, or as a passing slip in a prescient vision of the biological shape of things to come. But as often when Diderot spoke lightly, he meant this seriously as a complete repudiation of abstract conceptualization.

His rejection of mathematics was fundamental. He objected to its claim to be the true language of science on all grounds, metaphysical, mechanical, and moral. It is not just that mathematics idealizes. It falsifies, by depriving bodies of the perceptible qualities in which alone they have existence for an empirical, sympathetic science. Mathematics has turned mechanics into trivial description by mistaking the measurement of bodies for understanding the activity which animates them. Worst of all, the mathematical spirit is a blight. Fortunate but rare the mathematician whose own humane sensibilities are not blunted by his subject, which has fallen into aridity and circularity. So must any science do which ceases to “instruct and please.” Once idle curiosity is satisfied and novelty wears off, only its power to edify will keep a science living. “I do not except even natural history.”

More ominously, Diderot gives back to the Enlightenment, perhaps from his chemical studies, an angrier note, which echoes down the whole romantic movement. Mathematics is worse than inhumane. It is arrogant. In a sense, no doubt, everyone who has felt himself reach his mathematical frontier, whether at long division or out somewhere beyond the calculus, must know something of the helpless resentment engendered by the hidden beauty of the abstract. But Diderot’s own competence in mathematics was by no means contemptible. He fully appreciated its value as an instrument of precision in subordinate matters. His indictment is curious and interesting and not mere petulance. Mathematics is the science by which a finite intelligence purports to plumb the infinite. Now, man aspiring above himself incurs the classic guilt of hubris, the Christian guilt of pride. The prospect of an infinite universe has always disconcerted those who would render science humane. But Diderot was no Pascal to agonize over infinity. We are in the eighteenth century, and he responds with admirable nonchalance. He simply dismisses infinity as uninteresting. Since we shall need some criterion to establish bounds between knowledge and the infinite unknown, why let it be our interests. “It will be utility which, in a few centuries, will establish boundaries for experimental science, as it is about to do for mathematics.” And Diderot restores the mind, in a sense, to a finite cosmos, by wrapping science tight around humanity.

Nor in form are Diderot’s writings on nature an artless collection of aperçus. In the Dream of D’Alembert, that distinguished mathematical colleague is put into a trance, almost a delirium, out of which he speaks truths instantly recognized as such, and easily anticipated, by whom? His interlocutor is a doctor, the universal doctor, bending over the bedside of us all, who sees nature across the perspective of human nature, and who knew the answers all the time: “There is no difference between a doctor keeping watch and a philosopher dreaming.” And the apparent formlessness of the Interpretation of Nature is skillfully adapted to convey the congruence between man and nature. For it is written as a stream of consciousness, a reverie on the Experimental Art, the true route to a Science of Nature, moving out toward three objects: Existence, Qualities, Use. A threefold object, but a single purpose—what is the young man to look for in Diderot’s natural philosophy? “An abler than I will teach thee to know the forces of nature; it is enough for me to have made thee try thy own.”

Thus Diderot reverses Descartes, who studied himself to know nature. Diderot attends courses on chemistry. He reads Buffon, he studies nature—to know himself. But communication is direct, experiential. It does not lie through mathematics. It lies, instead, through craftsmanship. And this complicates the interpretation which makes the technology of the Encyclopedia an expression of the Newtonian spirit, which is to say of science. For Diderot, as for the chemists, truth opens to the common touch, and—as in Bacon—the importance of right method is that it dispenses the ordinary man from the need for genius. Genius, in its pride, is inclined to draw a mathematical shroud of obscurity between nature and the people.

Those are in error who say that some truths can never be put “at everyone’s disposal.” Certainly, ordinary people will never see merit in what cannot be proven useful. But in this, they see aright—or rather, they are aright to fail to see. Only experiential philosophy is an “innocent study,” in that it supposes no prior preparation of the mind. The habit of actually handling materials in dumb, untutored experiments, develops in him who performs the coarsest operations an intuition which has the character of inspiration. Manual facility gives a power of divination, the ability to “smell out—subodorer” how it must be with nature. But how do you know you have this power? How do you know you are right? It is—if the analogy is permissible—like awareness of Grace. It is like Virtue. It is participation in the Truth. You recognize it in yourself, in your own intimacy and more than intimacy, your solidarity with nature. In such a breast, science and nature are one, the reality of the great organism suffusing for the moment the material consciousness of the little. Not mathematical abstraction from nature then, but moral insight into nature, is the arm of science. Presuming to prescribe as rules for nature his own formulations, the scientist in his pride conceals from himself and others that it is not his laws of nature which are simple, but nature itself, in its essential unity.

For nature is the combination of its elements and not just an aggregate. Otherwise there is no philosophy—“Without the idea of the whole, philosophy is no more.” And Diderot, therefore, is bound to interest himself in continuity and not in divisibility: “Acknowledge that division is incompatible with the essence of forms, since it destroys them.” When he writes of molecules, it is of their transience, not their existence. In genetics, he rejects the notion (emboîtement) that each animal is contained full-formed in an infinite regression of ova reaching back through all the generations to the first creation. But it is the atomistic as well as the theological implications which Diderot finds unacceptable. For nature knows no limits. The male exists in the female, and vice versa (hence the curious fascination with hermaphroditism which runs through his writings). Mineral blends into mineral. The qualities of one living species penetrate in some degree the others. Minerals are themselves fused into living matter through the nexus of the plant which feeds on minerals and aliments the animals. Individual animals are real eddies of tighter organization, the ultimate but impermanent units, borne along a stream of seminal fluid flowing down through time and out from the matrix womb of nature herself. Even the physicist will do better to devote attention to what endures and spreads—to resonance, for example, to fire and electricity, to sulphurous exhalation, and to standing waves. Diderot, too, has a substitute for the universal attraction of corpuscular physicists: it is universal elasticity.

“Tout change; tout passe; il n’y a que le tout qui reste—Everything changes; everything passes; nothing remains but the whole.” And Diderot uses two figures to express this unity. The second is the more familiar, the universe as a cosmic polyp—time, its life unfolding; space, its habitation; gradience, its structure—for this embodies the twin ideas of universal sensibility and of what has often been called evolution. Diderot treats the continuous development of the universe as a consequence of the indivisibility of cosmic time. But his time—like his whole natural philosophy—is that of biological subjectivity, and in no way dimensional. And although this is consonant with historicism, there is (as will appear) no serious sense in which it foreshadows Darwinism. Not this, therefore, but rather the first of Diderot’s metaphors is the more significant. In it he evokes the swarm of bees. For the solidarity of the universe is social. On a cosmic scale, it is that oneness which the social insects know, among whom the laws of community are laws of nature. “Only the bad man lives alone,” he told Rousseau at their sad and angry parting. And in this social naturalism there is a more prescient (and to the liberal a more alarming) concordance between the whole and the parts, the one and the many, than in reversion to an antique hylozoism.

INDEED, Diderot was the Spinoza of biology before ever the science had its name—or its Newton. His was no feminine dislike of precision, no soulful sense of God in nature, but a philosophy of necessitarian organism. He would reach into the heart of science to turn it into moral philosophy. And now, looking back on that old sense of nature through Diderot’s clear eyes, we are prepared to grasp the meaning of Goethe’s more Delphic, his essentially poetic response to the world picture of Newtonian science. Being the man he was, Goethe would not simply lament the deprivation wrought by that tale of mournful numbers. He would do something about it. He would replenish the dream, not only with the Faust legend, and magic, “this one Book of Mystery/From Nostradamus’ very hand,” but also—“Thee, boundless Nature, how make thee my own?”—with the intermaxillary bone, the metamorphosis of plants, and a theory of colors as the “deeds and sufferings of light.”

Botany is the most accessible and consoling of the sciences, and (following in this Rousseau’s example) Goethe began with plants. He took up his Linnaeus to learn how to classify those he might encounter in his rambles about Weimar. But not for him the ticketing of static forms, not for him taxonomy—Linnaeus, he later said, had a greater influence on him than any thinker other than Shakespeare and Spinoza (for Goethe, too, would find destiny and necessity indwelling in flux and process, in the organismic and not the mechanistic universe). Though profound, Linnaean influence was repulsive. “For, even while I sought to assimilate myself to those sharp separations,… a conflict developed in my breast: That which he tried to separate by force of distinctions, tended by the most intimate necessity of my whole being to unite together.” There was in Linnaean botany nothing but nomenclature, nothing for the intelligence nor the imagination, no place for loveliness of form and flower. Counting stamens and pistils, it founded itself on numbers. Like some inhuman anatomist, Linnaeus could study a plant as well dead as alive. It was in this state that he habitually did study it, turning the stream of life into a mosaic of skeletons.

A friend of Goethe, a naturalist called Batsch, had developed an alternative system, one of the many “natural systems” of the eighteenth century. His practice ranged the plants by form according as they progressed along the chain of being. Goethe seized on the notion of progressive form. It was an ancient notion. On the principle that everything which can exist must exist, a perfect continuum of form rises from the lowest to the most high. Or must continually be rising, for it was Goethe’s view that no plant is to be taken simply as an object, ready made from the hand of the Creator. Growing things are to be studied in their cyclic living. One plants the seed. It burgeons. One follows the unfolding, day by day. Here is slow motion. At first imperceptible, the organs—never say when—appear. Now they differentiate themselves from the embryonic matrix of leaf-form. As the glory and the climax comes the end, the orgasm of the flower, dying into being, life’s withdrawal into death to return from the seed. And this is thrilling to observe, an affirmation and release after the pedantic, weary, and disgusting chore of classification, shuffling among minutiae as empty of meaning as the books littered about in Faust’s study.

Goethe’s Metamorphosis of Plants treats the plant as the epitome of all becoming. Unlike rootless organisms, the plant wears its inwardness outside for all to see. All are variations on the archetypal theme of an Urpflanz, deep down in being, way back in time: “All have a similar form, yet none is the same as the other. So this chorus of growth shows a mysterious law.” It is a true chorus. All the parts of a plant are variations on the single aboriginal organ, the Leaf, “the true Proteus,” out of which seed and form, stem and flower, successively permute:

Always changing, firm persisting

Near and far, far and near,

Thus in forming and transforming

To your wonder I am here.

And when in the 1790’s Goethe extended his interests to zoology, it was in the same idealistic vein. All animals are variations on an archetype; in the individual animal, the whole body is a succession of vertebral permutations. The skull is a metamorphosed vertebra, and this symmetrical theme further unfolds in the symmetry of the body. Hence Goethe’s joy in his discovery of the intermaxillary bone in man, all overgrown and merging into the maxillae, but there, as in progression from the great apes it should be, there and identifiable, an anatomical bond linking man morphologically yet a little more intimately into the rest of nature.

It is on turning to Goethe’s Teaching on Colors (for the literal translation of Farbenlehre conveys the spirit better than the more usual “Theory”) that one finds how inevitably this attempt to embrace all science in morphology implied repudiation of physics. “My Teaching on Colors,” he wrote, “is as old as the world, and in the long run it cannot be denied and thrust aside. These gentlemen may behave as they will, but at least they will not get this book out of the history of physics.” He wrote it only in 1810. But his passion for the subject was aroused in the Italian journey of 1786-87. Like many Germans he experienced the brilliance of that landscape as a revelation. Its pure, strong colors enchanted him. He watched the artists working with those colors. It came to him that “one must first get at colors as physical phenomena, from the standpoint of Nature, if one would gain control over them for purposes of Art.” Once again he turned to science and to the standard work. He took up Newton’s Opticks.

And again he was repelled by Newton as formerly by Linnaeus, and for the same reason. Anatomizing activity, Newtonian analysis takes what is whole to bits. It turns acts into husks. “As by an instinct,” he knew that Newton’s theory of colors was false. Then he borrowed a prism, and he saw (“Zum sehen geboren—to see is my birthright”) where Newton went wrong. The white wall opposite remained white though seen through the prism. Colors appeared only where the white was bounded by dark, as at the window frame. And how evident it is that edges bruise the light into colors, and that color manifests the tension between the primal polarities of light and dark. Light (for this is a syncretism between neo-Platonic and Stoic residues) is a streaming of reality, the manifestation of the immanent divine, as indivisible as soul. Darkness is suffering, not-being, death. Nor do colors simply register. Their perception is an optical act. So, for example, the eye may evoke them even when closed if it be struck a blow. But in normal circumstances it simply selects from the polarity what it needs to be at ease, demanding brightness when confronted by darkness, and for every color requiring its complement. Nor, though he looked through a prism, did Goethe believe in experiment. On the contrary, Newton’s errors were the price he paid for his methods, mathematicizing nature into abstraction, torturing her with instruments, with telescopes, prisms and mirrors, until she expires like a butterfly on a pin. Goethe would observe phenomena as they really are, under the open sky, without complicated and artificial arrangements, in a lifetime of sympathetic perception—

Friends, avoid the darkened prisons

Where they pinch and tweak the light

And in pitiful decisions

Bow to rays distorted quite,

Worshippers most superstitious

Thronged in plenty down the year.

Leave in hands of teachers vicious

Spectres, madness, cheats, and leers!

It is impossible to read the Farbenlehre without an acute sense of embarrassment at the painful spectacle of the author, a great man, making a fool of himself. Even the most rapt devotees have preferred to dwell upon his biological philosophy. And yet is it any better? Is not the advantage the biology seems to enjoy an illusion created by the lag between that science and physics? For really Goethe’s science is all of a piece with his personality, and with his poetry, as Bayard Taylor, perhaps the best of his translators, noticed many years ago. “His intellect had succeeded in uniting Man and Nature, the individual, the race, and the planet, in one consistent and harmonious scheme, wherein the poem and the mountain, the flower and the statue obeyed the same laws of growth.” Neither for the poet nor the scientist did the goal ever change:

That I may detect the inmost force

Which binds the world, and guides its course

Its germs, productive powers explore

And rummage in empty words no more.

In Germany, however, Goethe, the scientist, has always been taken seriously. The spate of solemn symposia shows no sign of slackening with the passing of the bicentennial. Nor is there any denying the importance of his influence in the nineteenth century. It was consonant with the idealist bent of philosophy in Germany. It eloquently reinforced that bent with the prestige of Germany’s greatest man of letters, her latter-day Leonardo, her universal man. A whole school of Naturphilosophie sprang up, or unfolded, to carry forward, or inward, the study of archetypal biology. It gave a great impetus to morphology and embryology. It would, of course, be an exaggeration to attribute the primacy of Germany in those studies to Goethe’s influence. Few important scientists were among the sectarians. Nevertheless, even fewer remained untouched by biological romanticism. It set the style of German science, as Cartesianism did (and still does) in France, and Baconianism in England. And Goethe’s influence may be taken as an instance, not just of cultural nationalism, but also of the anxiety of cultured scientists not to be divorced from culture by their own creation of science. If Goethe was right about enriching science with his insights, or even partly right, why science partakes of humanism in just that measure.

Nevertheless, the historian is bound to represent this Goethean intrusion as profoundly hostile to science, hostile to physical science and misleading, even if stimulating, to biology. Whatever the incidental contributions, it was biological romanticism which created the image of biology as a different kind of science. This was the origin of the distinction that makes life or organism, form or goal, the object of biology. This is what divided biology from physics on the supposition (or defense) that the biologist must characteristically study the nature and the wisdom of the whole rather than the structure or arrangement of the parts. In a sense, indeed, Goethe’s attack, and Diderot’s, upon Newtonian science may be seen as a wrong turning in that long dialogue which science has conducted throughout its history between the unity of nature and the multiplicity of phenomena. Against the wrecking into atoms, or fixed entities of any sort, whether light rays or Linnaean species, Goethe asserted the biological continuum, the stream of life.

Now, the continuum is by no means always the wrong side. Who studies to perceive the unity of nature necessarily adopts it (though at the price, perhaps, of unity of science). But the mathematical expression of the continuum was geometry, as in Einstein, as in the Newtonian void, as in Descartes, and ultimately back in Platonic mathematical realism. This is rational. It is objective, or may be. Not so the refuge

In the tides of Life,

In Action’s storm

A fluctuant wave

A Shuttle free

Birth and the Grave

An eternal sea

A weaving, flowing

Life, all-glowing.

Goethe’s nature is not objectively analyzed. It is subjectively penetrated. His is the continuum, not of geometry, but of sentience, not to say sentimentality. Nor does this vision of flux and process lead on to evolution in the proper sense. On the contrary, the unity of nature triumphs over the diversity of experience in universal metamorphosis. Man is neither product nor observer of nature. Instead, he is participant. He is communicant. For through the ashes between the surrender of Cartesian science and the rising of the Romantic phoenix, there ran this bond of dissatisfaction with a poverty in the Newtonian conception of scientific explanation. To the Cartesians, nature was the seat of rationality, and Newton’s laws appeared intellectually trivial. To the romantics, nature was the seat of virtue, and Newton’s laws were morally unedifying. The work of the romantics, therefore, had to be to preserve the continuity of man and nature by opening the personality to reality rather than the intellect. For if nature is congruent with man, if science is the correspondence, the universe has to be a continuum, a whole, a tout, as d’Alembert is made to see in his dream. But it is the whole personality which communicates, and not just the heart. Until Rousseau’s traumatic conversion, there is no question of irrationality.

Now, therefore, we may be in a position to venture that consistent account of romanticism which eludes us in the history of politics, philosophy, and the arts. Romanticism began as a moral revolt against physics, expressed in moving, sad, and sometimes angry attempts to defend a qualitative science, in which nature can be congruent with man, against a measuring, numbering science which alienates the creator of science from his own creation by total objectification of nature. For physics romanticism would substitute biology at the heart of science. For mechanism as the model of order, romanticism would substitute organism, some unitary emanation of intelligence or will, or else identical with intelligence or will. Romanticism might take any form in politics, art, or letters. But in natural philosophy there is an infallible touchstone of romantic tendencies. Its metaphysics treats becoming rather than being. Its ontology lies in metamorphosis rather than atomism. And always it wants more out of nature than science finds there.

Indeed, the renewals of this subjective approach to nature make a pathetic theme. Its ruins lie strewn like good intentions all along the ground traversed by science, until it survives only in strange corners like Lysenkoism and anthroposophy, where nature is socialized or moralized. Such survivals are relics of the perpetual attempt to escape the consequences of western man’s most characteristic and successful campaign, which must doom to conquer. So like any thrust in the face of the inevitable, romantic natural philosophy has induced every nuance of mood from desperation to heroism. At the ugliest, it is sentimental or vulgar hostility to intellect. At the noblest, it inspired Diderot’s naturalistic and moralizing science, Goethe’s personification of nature, the poetry of Wordsworth, and the philosophy of Alfred North Whitehead, or of any other who would find a place in science for our qualitative and aesthetic appreciation of nature. It is the science of those who would make botany of blossoms and meteorology of sunsets. And perhaps the humanist attempt to understand nature through self-knowledge, though never again to be the way of science, will always be the way of art. Not only of art, but of history, or rather historicism, for Herder’s seminal philosophy of history presupposes the same idea of nature as Diderot and Goethe held. Its reality is process and unfolding. Its laws are universal extensions of those which govern the birth, growth, and life course of the single organism. It saves the correspondence of microcosm and macrocosm by transposing it from space to time.

In a book on conservatism, one comes upon the following statement, appreciatively underlined by a succession of student readers, fortunate young men of the American élite: “Without the creative principle of voluntary action and a healthy degree of self-organization the organic life of society perishes in the arms of an efficient despotism, even though it takes unto itself the sacred name of democracy. The purpose of government is not to concentrate but to diffuse power. Diffusion of power is the characteristic of organic life, just as the concentration of power is the characteristic of mechanism.” And if one follows in imagination this lead from pure romanticism to the political realm, where the nexus of authority running between the one and the many really matters, it is almost alarming to think for a moment of the vast structures of reasoning about the state and society which depend upon substituting the metaphor of organism for atomism and mechanism. Where is Burke left without it? Where is the whole conservative apologia of the nineteenth century if it read the wrong science when it assimilated the ancient notion of the body politic to naturalism? What becomes of socialism if the idea of society as a collectivity, which it lifted from romantic conservatism, crumbles into atomistic (or individualistic) dust? Nothing, of course, would happen to political realities. But at least political apologists would be deprived of the right to draw dogmas from the nature of things and thrown upon their own resources—though since that is where Voltaire threw them two centuries ago, there is no reason to expect them to remain any more content with their own resources than other people do.

All of which is only to say that deep interests have been bound up with the romantic view of nature, deep interests and deep feelings, and also that it is the wrong view for science.