CHAPTER 7 Real Repugnance and Belief about Things - in - Themselves : A Problem and Kant ’ s Three Solutions

Kant famously claims that it can be rational to accept propositions on the basis of non-epistemic or broadly practical considerations, under certain circumstances, even if those propositions include “transcendental ideas” of supersensible objects. But he also worries about how such “ideas” (of freedom, the soul, noumenal grounds, God, the kingdom of ends, things-in-themselves generally) acquire positive content in the absence of an appropriate connection to intuitional experience. How can we be sure that the ideas are not empty “thought-entities [Gedankendinge]”—that is, speculative fancies that do not and perhaps even cannot have referents in reality (A771/B799)? This is a fair question, and when he is focused on it Kant often issues dire warnings about the casual employment of “empty” ideas, especially in metaphysical speculation: