Part III is dedicated to the critique of pure reason, namely, the discipline contained in the Critique that is charged with accomplishing its task as the doctrine of method of metaphysics. I argue that the critique of pure reason has a positive and a negative task. Chapter 5 is dedicated to its negative task. The critique must show that metaphysics is capable of systematic coherence. I take a body of cognitions to be systematically coherent when: (a) the cognitions belonging to it are interconnected in a way that involves relations of either logical implication, explanatory support or both, and (b) it does not contain contradictions. Kant establishes that metaphysics is able of systematic coherence by setting limits to cognitions. I argue that Kant sets these limits by limiting the validity of the root concepts for the cognition of objects analysed by transcendental philosophy. I consider how and where these limits are established. I claim, first, that Kant does not follow a univocal strategy in establishing these limits and, second, that he presents arguments for establishing these limits in the Aesthetic, Analytic, and Dialectic. I focus on the arguments in the Aesthetic and the Dialectic in particular.

Chapter 7 turns to the first two of the three metaphysical disciplines whose inferences and conclusions Kant discusses in the Transcendental Dialectic, namely, rational psychology and cosmology. We show how the four transcendental paralogisms and the arguments underlying the four antinomies of pure reason can be read as ‘necessary inferences of reason’ and how they result in the corresponding transcendental ideas. The chapter considers the paralogisms and the psychological ideas, discusses the role of transcendental realism in the paralogisms, looks at the derivation of the cosmological ideas and the four antinomies, and reconstructs the role of transcendental realism in the antinomies. In doing so, we concentrate on those aspects that are relevant to understanding how Kant develops his Rational Sources Account in the Transcendental Dialectic.