 In his “Introduction” to the Treatise, Hume launches the constructive phase of his project by proposing nothing less than “a compleat system of the sciences, built on a foundation entirely new” (T xvi.6). The new foundation is the scientific study of human nature. He argues that all the sciences have some relation to human nature, “even Mathematics, Natural Philosophy, and Natural Religion” (T xv.4). They are all human activities, so what we are able to accomplish in them depends on understanding what kinds of questions we are able to handle and what sorts we must leave alone. If we have a better grasp of the scope and limits of our understanding, the nature of our ideas, and the operations we perform in reasoning about them, there is no telling what improvements we might make in these sciences.