Present-day philosophers usually envision their discipline as an endeavor that has been, since antiquity, distinct from and superior to any particular intellectual discipline such as theology or science. Such philosophical concerns as the mind-body problem or, more generally, the nature of human knowledge they believe, are basic human questions whose tentative philosophical solutions have served as the necessary foundations on which all other intellectual speculation has rested. The basis for this view, however, lies in a serious misinterpretation of the past, a projection of modern concerns onto past events. The idea of an autonomous discipline called "philosophy," distinct from and sitting in judgment on such pursuits as theology and science, turns out, on close examination, to be of quite recent origin. When, in the seventeenth century, Descartes and Hobbes rejected medieval philosophy, they did not think of themselves, as modern philosophers do, as proposing a new and better philosophy, but rather as furthering "the warfare between science and theology." They were fighting, albeit discreetly, to open the intellectual world to the new science and to liberate intellectual life from ecclesiastical philosophy and envisioned their work as contributing to the growth, not of philosophy, but of research in mathematics and physics. This link between philosophical interests and scientific practice persisted until the nineteenth century, when decline in ecclesiastical power over scholarship and changes in the nature of science provoked the final separation of philosophy from both. The demarcation of philosophy from science was facilitated by the development in the early nineteenth century of a new notion, that philosophy's core interest should be epistemology, the general explanation of what it means to know something. Modern philosophers now trace that notion back at least to Descartes and Spinoza, but it was not explicitly articulated until the late eighteenth century, by Kant, and did not become built into the structure of academic institutions and the standard self-descriptions of philosophy professors until the late nineteenth century. Without the idea of epistemology, the survival of philosophy in an age of modern science is hard to imagine. Metaphysics, philosophy's traditional core – considered as the most general description of how the heavens and the earth are put together – had been rendered almost completely meaningless by the spectacular progress of physics. Kant, however, by focusing philosophy on the problem of knowledge, managed to replace metaphysics with epistemology, and thus to transform the notion of philosophy as "queen of sciences" into the new notion of philosophy as a separate, foundational discipline: philosophy became "primary" no longer in the sense of "highest" but in the sense of "underlying." After Kant, philosophers were able to reinterpret seventeenth-and eighteenth-century thinkers as attempting to discover "How is our knowledge possible?" and to project this question back even on the ancients.