Kant's Transcendental Deduction by Alison Laywine

Alison Laywine's contribution to the rich literature on Kant's "Transcendental Deduction of the Categories" stands out for the novelty of its approach and conclusions. Laywine's declared "strategy" is "to compare and contrast" the Deduction with the Duisburg Nachlaß, an important set of manuscript jottings from the 1770s (10). But her approach is also deeply informed by Kant's writings on metaphysics from the 1750s and 1760s; moreover, she gives attention to ancient Greek geometry and its importance for Kant's thought.

I believe Laywine's most important interpretative claim is that the Transcendental Deduction's "final step" addresses "the question of how nature is possible" (210). Here, 'nature' is understood in what Kant calls the "formal sense," as "the totality of rules under which appearances must stand if they are to be thought as joined in one experience" (Prolegomena, §36; cf. B 165). This constitutes a novel answer to the problem posed in Dieter Henrich's landmark 1969 paper "The Proof Structure of the Transcendental Deduction" (Review of Metaphysics 22 [1969]: 640–59): how to understand §§21–26 of the (B-edition) Deduction as proving more than the thesis already stated in §20 (that the manifold in an intuition necessarily stands under the categories).

Crucial support for Laywine's interpretation comes from §26 of the Deduction, which claims the possibility of cognizing objects "a priori through categories . . . as far as the laws of their combination are concerned, thus the possibility of as it were prescribing the law to nature and even making [nature] possible," is now "to be explained" (B 159). Kant does not use the term 'world' in this passage (as he does in Prolegomena §36). But Laywine contends that here the word 'nature' "has unmistakable, deliberate, cosmological connotations," and in fact "means 'world' in the sense of Kant's early cosmology": roughly, a whole unified by means of laws (12–13).

The "cosmological" language of §26 does not recur in the following, officially concluding, section of the Deduction. So, we might ask whether Kant's explanation of how the understanding prescribes laws to nature is integral to the Deduction; Henry Allison, for instance, describes this explanation as an "appendix" (Kant's Transcendental Deduction: An Analytical-Historical Commentary [Oxford: Oxford University Press, 2015], 9). The question of whether it belongs integrally has bite because, as Laywine makes clear in her "Conclusion," the universal laws at issue are just the Analogies of Experience. Thus, the passage could be read as the "promissory note with a forward-looking reference to the System of Principles" that she finds missing from the Deduction (289). Laywine meets such worries by arguing that "the reappropriation [from the pre-Critical period] of the general cosmology is actually doing . . . a lot of hard work" in the Deduction (13). This sustained argument comes to a head in chapter 4, which contends that each of the two steps into which Laywine divides the first half of the (B-edition) Deduction, treated in chapters 2 and 3 (respectively), relies on cosmological presuppositions.

Chapter 2 analyzes the conception of knowledge as relation to an object that is asserted (in §17) to rely on the synthetic unity of apperception. Laywine traces this conception to the Duisburg Nachlaß's account of "exposition," which relates concepts a priori to appearances, in something like the way that geometrical construction relates them to pure intuition. (Laywine further connects the Latin term expositio to the Greek ekthesis, which expositio translates in the context of geometrical proof. She thereby gives the notion of ekthesis broader importance than does Jaakko Hintikka, who noted its relevance to Kant's philosophy of mathematics in "Kant on the Mathematical Method" [Monist 51 (1967): 352–75]. Laywine claims that Borelli's edition of Euclid could have been Kant's source for the term, but I doubt it was known to Kant and his contemporaries, since it is not among the editions cited by Christian Wolff; Commandino seems likelier to me. Chapter 2 is concerned to articulate the notion of "self-activity," which makes possible the relation to the object, on Laywine's reading, and links this notion to the synthetic unity of apperception. In chapter 4, Laywine argues that this conception of knowledge "is incomplete or inoperative . . . unless paired with Kant's conception of our understanding as a legislator" (218), and that "the relation between knowledge and its object" depends specifically on "the universal laws prescribed to nature by the understanding" (219).

Chapter 3 considers how §§18–19 of the (B-edition) Deduction, on "objective" and "subjective" unities of consciousness and on judgment, complete its first half. On Laywine's account, the use of concepts in judgment, where the relation to the object is "expressed as" a truth-value, "fully realize[s] the objective quality of the synthetic unity of pure apperception that constitutes [concepts] as such" (208). In chapter 4, Laywine does not identify cosmological presuppositions of judgment as such, but rather argues in general terms that the use of concepts presupposes "a single, unified, universal experience that embraces all of what . . . can appear in a structured, law-governed system of some kind" (221). Thus the understanding, characterized as a faculty for using concepts, must be conceived as legislative, because Kant's "only way . . . to account for such a totality is to invoke an analogue for divine legislation, as elaborated in his early cosmology" (221). Anticipating the objection that Kant's Critical rejection of speculative metaphysics rules out such notions of totality, Laywine explains why they are not subject to demands by Reason that generate antinomial conflicts.

The remainder of chapter 4 concerns the necessary conditions on perception stated in §26 of the (B-edition) Deduction. Laywine's focus is on the intuitions of space and time here distinguished from space and time as forms of intuition. Laywine takes Kant to argue that perception must "conform to" these intuitions' "synthetic unity" (240), which then makes it possible to represent perceived objects "relative to one another in one and the same universal experience," situating them on a "map of the phenomenal world" (244). Laywine then argues that this "cosmological cartography" depends on universal laws prescribed to nature by the understanding (259–61). It might now seem that Henrich's challenge goes unmet, since on Laywine's reading such laws are already presupposed by the "relation to the object" thematized in the Deduction's first half. But the "cartography" of §26 is indispensable because its dependence on the laws is reciprocal; it is the ekthesis needed to make the laws understandable to us. Chapter 5 completes Laywine's account of the Deduction's second half by arguing that "cartography" is also required for empirical self-knowledge.

Laywine's strategy of relating the Deduction to cosmological considerations and to the Duisburg Nachlaß leaves the Deduction somewhat unmoored from surrounding portions of the Critique. For instance, section 2a of chapter 2 appeals to the 1763 Beweisgrund to elucidate Kant's notion of "manifold" and its applicability to concepts, bypassing §10 of the Leitfaden section, which clearly distinguishes between the synthesis that unifies a manifold and the concepts that "give this synthesis unity" (A 79/B 104). Laywine's claim that a reason is needed for thinking that "the space and time of" distinct perceptions "are somehow related" (242) is puzzling in light of Kant's insistence in the Transcendental Aesthetic on the singularity and what we could call connectedness of space and time, which Laywine seems to discount with her later clarification that the unity ascribed to them in the Aesthetic is "just whatever makes any determinate . . . magnitude a continuous one" (254). But even if these or other details have more proximate sources or explanations, Laywine's appeal to Kant's cosmology and the development of his metaphysics powerfully illuminates the Transcendental Deduction as a whole.