 Fodor (1987: 18–20) argues that CCTM+FSC helps illuminate a crucial feature of cognition: semantic coherence. For the most part, our thinking does not move randomly from thought to thought. Rather, thoughts are causally connected in a way that respects their semantics. For example, deductive inference carries true beliefs to true beliefs. More generally, thinking tends to respect epistemic properties such as warrant and degree of confirmation. In some sense, then, our thinking tends to cohere with semantic relations among thoughts. How is semantic coherence achieved? How does our thinking manage to track semantic properties? CCTM+FSC gives one possible answer. It shows how a physical system operating in accord with physical laws can execute computations that coherently track semantic properties. By treating the mind as a syntax-driven machine, we explain how mental activity achieves semantic coherence. We thereby answer the question: How is rationality mechanically possible?