 Kant agrees with Hume that neither the relation of cause and effect nor the idea of necessary connection is given in our sensory perceptions; both, in an important sense, are contributed by our mind. For Kant, however, the concepts of both causality and necessity arise from precisely the operations of our understanding—and, indeed, they arise entirely a priori as pure concepts or categories of the understanding. It is in precisely this way that Kant thinks that he has an answer to Hume’s skeptical problem of induction: the problem, in Kant’s terms, of grounding the transition from merely “comparative” to “strict universality” (A91–92/B123–124). Thus in § 29 of the Prolegomena, as we have seen, Kant begins from a merely subjective “empirical rule” of constant conjunction or association among our perceptions (of heat following illumination by the sun), which is then transformed into a “necessary and universally valid law” by adding the a priori concept of cause.