 The Transcendental Dialectic, the second half of the Critique of Pure Reason in which Kant provides the critique of traditional metaphysics is explicitly intended to give an indirect proof of transcendental idealism (B xx). Specifically, the middle section of the Dialectic, entitled “The Antinomy of Pure Reason”, is supposed to provide this indirect proof. All three sections of the Dialectic, thus the preceding “Paralogisms of Pure Reason” and the following “Ideal of Pure Reason”, are supposed to show that the faculty of reason’s inevitable conception of the “unconditioned”, that which is a condition for everything else but itself has no condition, can never provide knowledge of any object because knowledge requires intuition as well as concept, and intuition is always conditioned—the representation of any region of space is conditioned by more surrounding it, and that of any region of time is likewise conditioned by the representation of more time before and after it. Reason can form “transcendental ideas”, more properly, “transcendent concepts” (A 327/B 384), that is, the ideas of an unconditioned subject (the self as substance), an unconditioned whole of all things and events (a completed world-whole), and an unconditioned ground of all possibility (God) (A 334/B 393). These ideas, according to Kant, may be useful as guidelines for scientific research and even necessary for the purposes of practical reason, but they outrun the limits of intuition and therefore theoretical cognition. This general claim itself does not entail transcendental idealism, that is, it does not identify space and time with our own forms of intuition. However, Kant’s claim is that the paradoxes diagnosed in the “Antinomy of Pure Reason” can only be resolved on the basis of transcendental idealism. In the case of the first two antinomies he argues that both sides essentially concern space and time or the things in them (these are the arguments that as we saw were missing from Arthur Collier’s anticipation of the first two antinomies), and that since space and time as forms of intuition are indefinitely extendable and divisible, both sides of the debates, the theses and the antitheses, are false: space and time and thus the totality of things and events in them (the world) are neither bounded and finite or unbounded and infinite but indefinite (even though particular things within space or periods within time may have determinate boundaries). In the case of the third and fourth antinomies, however, Kant argues that the distinction between appearances and things in themselves that is at the heart of transcendental idealism makes it possible for both sides to be considered true, since they concern different objects: in the empirical world of experience, there are only ever indefinitely extending chains of causes and effects, each moment of which is necessary relative to its causal laws (the third antithesis) but contingent because no antecedent cause is absolutely necessary or necessary considered in itself, but outside of the empirical world there is nothing to prevent there being an absolutely necessary thing in itself (God) nor acts of absolute spontaneity on the part of that absolutely necessary being or even lesser beings, such as finite agents. Thus, Kant argues that the antitheses of the third and fourth antinomies are actually true of the world as it appears, while the theses of these two antinomies are possibly true of things in themselves, namely of God as the ground of the entire world of appearance and of ourselves as spontaneous agents grounding our own appearances of action. Again, Kant’s ultimate claim will be that we have necessary and sufficient practical grounds for affirming both our own freedom and the existence of God, but these do not yield theoretical cognition (B xxx).