TNH 1.3.03.05
So the opinion of the necessity of a cause for every new production isn’t based on ·a priori· knowledge or scientific reasoning, and must therefore arise from observation and experience. The natural next question is: how does it arise from experience? But I shall postpone that for a while, because I find it more convenient to sink this question in two others:
•Why do we conclude that such-and-such particular causes must necessarily have such-and-such particular effects?
•Why do we form an inference from cause to effect?
It may turn out eventually that a single answer will serve for both questions.