A feature of the current situation in philosophy is that philosophers experience difficulty in explaining precisely what it is they do. A reason for the embarrassment is that so much of the original terrain of philosophy has been taken over by disciplines of latter-day origin that it is possible to think the whole of philosophy will eventually metamorphose into science and the ranks of the unemployed will become swollen with erstwhile seekers after wisdom. It was a response to this seeming threat to suggest that philosophy has no subject matter of its own but is a second-order discipline whose task it is to reflect critically on what is going on in disciplines that do have a subject matter. Hence, perhaps, the proliferation of such activities as philosophy of science, philosophy of history, philosophy of art, and so on.
Whatever the present situation, Thomas Aquinas operated with a conception of philosophy that had come to him from the Greeks. Understood as the pursuit of wisdom, philosophy becomes an umbrella concept under which are gathered all disciplines that are necessary for or conducive to the acquisition of wisdom, and wisdom is taken to be such knowledge as men can attain of the divine. Classically understood, the ultimate aim of the philosophical quest is called not only wisdom but also theology. For Aristotle, what we would call natural sciences—and he was the originator of many of them—were essential elements of philosophical activity, not something distinguished from it. He held this view because he held that it is only through knowledge of the natural world that we can come to such knowledge as we do of things divine. Logic, natural sciences, mathematics, ethics and political philosophy, literary criticism, indeed all the liberal arts, were sought not onlv for their own sakes but as stepping stones to the culminating science of metaphysics. It could be said that, in its classical conception, philosophy included most of what is done in our universities. One can only imagine Aristotle's puzzlement, accordingly, if he were to come upon a department of philosophy distinguished from many other departments. How can philosophy be understood as a specialty? It would have boggled his mind. Thomas would have found our situation equally surprising.
(Ralph McInerny, Ethica Thomistica: The Moral Philosophy of Thomas Aquinas, rev. ed. [Washington, DC: The Catholic University of America Press, 1997], 114-5)
