Abstract: One of the most important philosophical contributions made by the later Wittgenstein is to distinguish reason from cause. On the basis of this distinction, he discussed the rule-following and the nature of language. This distinction plays a central role not only in Wittgenstein’s philosophy, but also in contemporary discussions on issues in moral philosophy and philosophy of action. On mine mind, Wittgenstein is the first philosopher in history who makes the distinction. But some philosophers don’t think so. For example, Allison, one of the most important experts in Kant, claims that Kant already made, or at least should have made, this distinction in his doctrine of intelligible causation. I shall argue that this is a completely wrong interpretation of Kant’s doctrine.