While Chapter 3 was dedicated to metaphysical deductions, this chapter reconstructs transcendental deductions, which I take to accomplish the second task of transcendental philosophy as it is established in the Critique of Pure Reason. Transcendental deductions are tasked with determining that root concepts (Stammbegriffe) have objective validity. In a way similar to my analysis of metaphysical deductions, I identify a transcendental deduction of space and time in the Aesthetic, a transcendental deduction of the categories in the Analytic and a transcendental deduction of ideas in the Dialectic. However, objective validity does not mean the same in all these cases. I take it that the main sense in which Kant uses the term is the following: concepts have objective validity when through them we cognize something that really pertains to objects. This is not the sense of objective validity that Kant uses with respect to ideas. In this case, claiming that ideas are objectively valid means attributing to them what I call the ‘practical’ and the ‘indirect’ validity of ideas. I argue that transcendental deductions only establish positive results regarding the validity of the root concepts and are not tasked with determining limits of this validity.

The concluding chapter sketches a portrait of Kant the empiricist and highlights what is of broader philosophical interest in it. Kant has a keen understanding that empirical knowledge is gradually acquired through a process of revision and refinement. Empirical knowledge is not an epistemic state but a process – not a possession but an ongoing pursuit. This follows from making a regulative assumption a necessary condition of empirical experience and knowledge. Furthermore, only the complete but unattainable determination of the sensibly given by a complete system of causally explanatory concepts can ground the objectivity and truth science seeks. Empirical truth too is ultimately an end we continuously pursue. Our claims to knowledge and our attempts at scientific explanation lay claim to being objectively true. But they are in principle open to revision, refinement or outright rejection. The chapter further claims that Kant’s conception of the aesthetic purposiveness of nature is an account of the acquisition of our most fundamental empirical concepts of observation, which also explains the fact that what we most fundamentally perceive are unchanging simple objects and their salient sensible properties. Finally, it shows that the aesthetic condition of experience does not prey to the "myth of the given."

Chapter 3 tackles the considerable exegetical difficulties posed by the antinomy of teleological judgment. Although the Dialectic of Teleological Judgment poses an antinomy between regulative maxims of reflective judgment, it also presents a conflict between would-be constitutive principles of determinative judgment. This fact has led a number of readers to conclude that the latter conflict is the antinomy of teleological judgment and the former is its resolution – Kant’s explicit claims to the contrary notwithstanding. The chapter argues that posing the conflict between would-be constitutive principles of determinative judgment is explained by the attempt to assimilate characteristic features of a dialectic, specifically the fact that it ensnares ordinary understanding. Building on the earlier discussion of the distinction between explanation and description, it further claims that the regulative maxims of reflective judgment do not contradict one another, even as they are first presented, but in fact essentially complement one another. The maxim of teleology governs the description or observation of organisms as self-organizing beings; the maxim of mechanism directs us to seek to explain their generation and the processes they undergo mechanistically, just as all other causal processes are to be explained.