In The Therapy of Desire ( Chapter: “Medical Dialectic: Aristotle on Theory and Practice”), Martha Nussbaum notes that Aristotle’s theories are based on his study of human experience. Here’s an excerpt:
All Aristotelian inquiries, ethics included, are bounded by the “appearances”—by human experience. In none does there appear to be the possibility of confirming results by comparison to an altogether extraexperiential reality. On the other hand, Aristotle does not mourn the absence of such standards: for the boundaries of experience are also, he holds, the boundaries of discourse and thought. The search for truth is the search for the most accurate account of the world, as we do (and shall) experience it. But this is unqualifiedly a search for truth; and no apologies need be made for using that word.
Ethics, however, relies on human experience in a stronger sense. First, what it aims to describe is the good life for a particular species: and in so doing it must consider that species' characteristic capabilities and forms of life. The good human life must, in the first place, be such that a human being can live it: it must be "practicable and attainable for the human being" (Nicomachean Ethics). This is no trivial requirement. And in fact, Aristotle seems to hold something far stronger: the good life must be "common to many (polukoinon): for it is capable of belonging to anyone who is not by nature maimed with respect to arete, through some sort of learning and effort" (Nicomachean Ethics). (It is important to bear in mind that in Aristotle's view not many people are so "maimed": nothing like a view of original sin plays any role in his thinking.) He rejects the view that the good life is primarily a matter of luck or innate talent-and rejects these views as false ethical views—not on the grounds that some independent cosmic evidence refutes them, but on the grounds that such a view would "strike too false a note" (Nicomachean Ethics), be too out of line with people's aims and hopes.Aristotle’s philosophy is valuable because it is based on facts which he discovered by studying the experiences of the people who were part of his world. He also studied the views of the major Greek artists, politicians, scientists, historians, and philosophers—it is noteworthy that his work on almost every subject begins with a reference to the ideas of the past thinkers on that subject.