WHAT, NEXT, about the Pyrrhonian problem of a balance of opposing arguments in metaphysics? How does the critical philosophy undertake to save its reformed metaphysics from this skeptical problem?
The first point which deserves emphasis here is that Kant evidently saw his solution to the Hume-influenced problems as the key to solving this Pyrrhonian problem as well. This can be seen from the following passage in the Critique: “The proper problem of pure reason is contained in the question: How are a priori synthetic judgments possible? [I.e., one of the Hume-influenced problems.—M.N.F.] That metaphysics has hitherto remained in so vacillating a state of uncertainty and contradiction [i.e., the Pyrrhonian equipollence problem—M.N.F.], is entirely due to the fact that this problem . . . has never previously been considered. Upon the solution of this problem . . . depends the success . . . of metaphysics.”1 Indeed, I would suggest that for Kant the importance of the Hume-influenced problems ultimately lay at least as much in the fact that their complete solution promised also to make possible a solution to the Pyrrhonian problem as in the intrinsic force that he saw in them.
How does Kant envisage his solution to the Hume-influenced problems enabling him to save metaphysics from the Pyrrhonian problem as well? Part of what he has in mind here is that his solution to the Hume-influenced problems makes possible a solution to the canonical four Antinomies. Thus shortly after the passage just quoted he goes on to give as an example of the sort of question that has “always met with unavoidable contradictions” the First Antinomy’s question “whether the world has a beginning or is from eternity.”2 To this extent, Kant’s idea is that the Hume-influenced problems about (a priori concepts and) synthetic a priori knowledge in metaphysics demand transcendental idealism as part of their solution, and that transcendental idealism then serves as the means for resolving the Antinomies as well.
It does so, according to the Critique, by showing the apparent conflicts involved in the Antinomies to be illusory.3 It accomplishes this in roughly the following way.4 In the case of the “Mathematical” Antinomies, we have (Kant alleges) compelling arguments both for denying the thesis and for denying the antithesis—e.g., in the First Antinomy, both for denying the thesis that the world has a beginning in time and for denying the antithesis that it lacks a beginning in time and hence is eternal.5 Since these two possibilities appear to be, not only logically exclusive of each other, but also logically exhaustive, this seems to lead to an unresolvable contradiction, for it seems that we can infer from the disproof of each to the truth of the other. However, if, and only if, we embrace transcendental idealism’s claim that the whole spatio-temporal world is merely an appearance, not a thing in itself, then we can escape this apparent contradiction. For in that case, and only in that case, the two possibilities are not in fact logically exhaustive after all, since, according to Kant, whenever a subject concept is empty (or, more specifically, self-contradictory)6 opposite predications concerning it are both false. Consequently, if, and only if, the whole spatio-temporal world is merely apparent (as transcendental idealism holds), then the two equally compelling arguments of a “Mathematical” Antinomy do not really contradict each other after all; both thesis and antithesis can be false, as the arguments (allegedly) prove that they are.7
In the case of the “Dynamical” Antinomies, we have (Kant alleges) compelling proofs both for the thesis and for the antithesis—e.g., in the Third Antinomy, both for the thesis that there is freedom, or uncaused causation by the will, and for the antithesis that there is no freedom but instead only thoroughgoing causation. This again seems to leave us with a contradiction. However, if, and only if, transcendental idealism’s claim that the realm of nature is merely apparent and distinct from the realm of things as they are in themselves is correct, then the thesis and the antithesis can in fact be, not contradictory, but consistent with each other and both true (namely, of different realms). So, once again, if, and only if, transcendental idealism is true, then these Antinomies can be resolved.8
So much for resolving the canonical four Antinomies. However, as I suggested earlier, Kant’s concern in the Critique about the problem of metaphysics’ “vacillating . . . state of uncertainty and contradiction” really still extends beyond the canonical four Antinomies (as in the precritical period). And one may therefore reasonably ask whether his idea of solving this problem via his solution to the Hume-influenced problems does not include more than just the above, relatively well-known, strategies for addressing the four Antinomies. I believe that it does, that it also includes a further, and much less well-known, strategy designed to liberate metaphysics from Pyrrhonian equipollence skepticism more broadly.
Shortly after the passage from the Critique recently quoted in which he indicates that the problem of metaphysics’ “vacillating . . . state of uncertainty and contradiction” can, and can only, be solved via the solution to the Hume-influenced problem concerning synthetic a priori knowledge, Kant returns to the topic of the problem of “unavoidable contradictions” in metaphysics, describing this as a threat of “dogmatic assertions to which other assertions, equally specious, can always be opposed—that is . . . skepticism.”9 And he indicates the following strategy for solving it: “It must be possible for reason to attain to certainty whether we know [Wissen] or do not know [Nicht-Wissen] the objects of metaphysics, that is, to come to a decision either in regard to the objects of its enquiries or in regard to the capacity or incapacity of reason to pass any judgment upon them, so that we may either with confidence extend our pure reason or set to it sure and determinate limits.”10 This obscure passage implies, I think, a twofold strategy for addressing the Pyrrhonian equipollence skeptic: on the one hand, produce certain knowledge of some bits of metaphysics by establishing both the facts in question (“the objects of its enquiries”) and our ability to know them (“the capacity . . . of reason to pass any judgment upon them”); on the other hand, produce certain knowledge that in relation to other metaphysical matters we do not and cannot have knowledge.11
The further twofold strategy that Kant has in mind here is, I suggest, more specifically as follows. First, he believes—not unreasonably, given his understanding of Pyrrhonism as a rather restrained form of skepticism—that his solutions to the Hume-influenced problems on behalf of particular metaphysical concepts and principles by proving that these refer / are true and by explaining the possibility of our achieving reference / knowledge with them are such that the Pyrrhonist is bound to accept these solutions as well. Consider, in particular, Kant’s transcendental argument proofs that. Kant apparently understands the conditional propositions of the form “Necessarily if there is experience (of such-and-such a type), then a priori concept C refers / synthetic a priori principle p is true” which constitute the core of these proofs to be just as irresistible for a Pyrrhonist, once demonstrated to him, as they are for the Hume-influenced skeptic. For Kant believes the Critique’s essential contents generally, and, one must therefore infer, such propositions as these and the demonstrations given for them in particular, to be “the measure, and therefore . . . the paradigm, of all apodeictic . . . certainty.”12 Furthermore, the Pyrrhonist, as Kant conceives him, does not in general question experiential judgments.13 He is therefore also bound to accept the proposition “There is experience (of such-and-such a type).” Finally, there is no question of Kant’s Pyrrhonist questioning logical principles, such as modus ponendo ponens.14 And so he is bound to infer from those two premises the consequents of the conditional propositions involved: propositions of the form “A priori concept C refers / synthetic a priori principle p is true.” A similar points applies to Kant’s transcendental idealist explanations of the possibility of our referring with / knowing particular metaphysical a priori concepts and synthetic a priori principles: since these explanations are among the essential contents of the Critique, they too are evidently understood by Kant to possess “apodeictic . . . certainty.”15 In sum, Kant thinks that the Pyrrhonist cannot but accept the proofs and explanations which he has already given vindicating particular metaphysical concepts and principles. These parts of metaphysics at least can therefore be saved from the threat of a Pyrrhonian balance of opposed arguments in Kant’s view.
The second side of Kant’s further twofold strategy for freeing metaphysics from the Pyrrhonian problem by building on his solutions to the Hume-influenced problems is as follows. Providing, in the manner just described, a defense that is compelling for the Pyrrhonist of some modest number of metaphysical concepts and principles would in itself settle only a small subset of the myriad “civil wars” between metaphysical claims to which the Critique attributes skepticism about the discipline of metaphysics.16 However, Kant envisages a way of proceeding from this modicum of metaphysical peace to the end of all disputes in metaphysics, and hence to the complete liberation of the discipline from the bane of the Pyrrhonian problem. His strategy is not to settle the remaining disputes, but rather to show that they do not belong within the discipline of metaphysics.
How does he propose to achieve that? One essential pillar supporting his case is his fundamental assumption that metaphysics, properly so called, is of its very essence a science (Wissenschaft). (Recall his remark that “metaphysics must be a science . . .; otherwise it is nothing at all.”17) This implies, at a minimum, that its principles must not only be true but must also constitute knowledge (Wissen). Another essential pillar supporting his case is a conviction that his solutions to the Hume-influenced problems, his proofs and explanations for particular metaphysical a priori concepts and synthetic a priori principles, not only establish that these do afford knowledge in the domain of metaphysics, but also furnish a basis for demonstrating that other principles which are currently counted by people as belonging within that domain cannot constitute knowledge. This is what he has in mind when he writes that the critical philosophy furnishes in connection with metaphysics “a standard . . . to our judgment whereby knowledge [Wissen] may be with certainty distinguished from pseudo-knowledge [Scheinwissen].”18 He believes that the demonstration in question in fact shows that none of the principles currently counted by people as falling within the domain of metaphysics except for those which he has vindicated in the course of solving the Hume-influenced problems can constitute knowledge. If this can indeed be shown, then, given the fundamental requirement that metaphysics must of its very nature be knowledge, all of these other principles may quite properly be expelled from the domain of metaphysics and left to conduct their “civil wars” elsewhere.19
How, though, does Kant hope to demonstrate that all principles currently counted by people as belonging within the domain of metaphysics except for those which he has vindicated in the course of solving the Hume-influenced problems can constitute nothing more than pseudo-knowledge? The answer to this question lies in his conviction that (as he puts it in the Critique) “metaphysics . . . is the only science which promises . . . completion,” and that the critical philosophy can achieve a demonstrably “complete cognition” of “reason itself and its pure thinking.”20 By this, he means that the critical philosophy can demonstrate the completeness of the conceptual sources and fundamental principles of metaphysical knowledge which it vindicates in answer to the Hume-influenced problems, their exhaustion of metaphysical knowledge.
But how can it do that? The demonstration turns crucially on the critical philosophy’s claim to show that these conceptual sources and fundamental principles of metaphysical knowledge constitute together an entire system.21 For it is a central and recurrent theme in Kant’s thought that the way to demonstrate that an aggregate of items of some particular kind is a complete collection of items of that kind is to show that they constitute together, not only all items of that kind which one can discover, but also an entire system.22 (Note that the inference here from entire system to complete collection is not, as it might initially appear, a trivial one.23)
Accordingly, in an important passage from the Von Schön Metaphysics Kant implies that the full solution to the problem of equipollence skepticism afflicting metaphysics lies, not only in validating specific conceptual sources and fundamental principles of metaphysical knowledge by proving that and explaining how they constitute such, but also in establishing that the sphere of the conceptual sources and fundamental principles of metaphysical knowledge is thereby exhausted through showing that they constitute together an entire system.24
The critical philosophy’s demonstration in answer to equipollence skepticism that its collection of the conceptual sources and fundamental principles of metaphysical knowledge is complete therefore ultimately rests on the notorious systematic, or “architectonic,”25 aspects of the Critique, which aim to exhibit the entire systematicity of those sources and principles.26
More specifically, Kant’s idea is as follows: Given that the twelve logical forms of judgment constitute an entire system, it can be demonstrated that our collection of metaphysical a priori concepts of the understanding does so as well by showing that they correspond one-to-one with those logical forms of judgment.27 And given now that our collection of metaphysical a priori concepts of the understanding constitutes an entire system, it can be shown that our collection of metaphysical synthetic a priori principles does so as well by showing that they in turn correspond one-to-one with the metaphysical a priori concepts of the understanding.28
To give a particular example of how these correspondences are supposed to work: the hypothetical form of judgment “If p then q” corresponds to the a priori concept of causation, since it yields the idea of the consequence (Konsequenz) of one thing upon another that is the core of the concept of causation;29 and the a priori concept of causation then in turn corresponds to the synthetic a priori principle that every event has a cause (this time for obvious reasons).
Since, in Kant’s view, the Critique’s demonstration that its collection of the conceptual sources and fundamental principles of metaphysical knowledge is complete possesses, like the rest of the work’s essential contents, “apodeictic . . . certainty,” it will again, in his view, be such that the Pyrrhonist cannot but accept it once it is laid out for him. Consequently, the Pyrrhonist can be compelled to admit, not only that these sources and principles provide metaphysical knowledge (in the way explained earlier), but also that all of the remaining principles whose battles have hitherto sullied and might continue to sully the name of the discipline in fact belong outside it.
This, then, is Kant’s grand strategy in the critical philosophy for defending a reformed metaphysics against the various skeptical problems that had originally arisen to threaten the discipline in the mid-1760s to early 1770s, causing him to reform it in order to enable it to withstand them. Reformed and defended against those skeptical problems in the ways sketched above, metaphysics at last in the critical philosophy emerges “on the secure path of science.”30 Such, at least, is Kant’s belief.