In this Chapter, I consider what is undoubtedly the most original and influential part of the Treatise, namely Part 3 of Book 1, where Hume presents his theory of causation. It is easy to lose sight of his central discovery concerning causation as we go through the details of his theory. While Hume scholars disagree on some of these details, there is general agreement that this central discovery was epistemological and that it had profound results in our intellectual history. Hume expresses his central epistemological claim toward the end of Part 3 when he writes that

Before Hume, major thinkers held that we have some knowledge independently of experience as to what kinds of things can and can't produce other kinds of things. Even Newton and Locke held that it is impossible for the order we discover in the universe to arise from anything but a thinking intelligent being.