             However we arrive at secure principles in philosophy and science, whether by some process leading to a rational grasping of necessary truths, or by sustained dialectical investigation operating over judiciously selected endoxa, it does turn out, according to Aristotle, that we can uncover and come to know genuinely necessary features of reality. Such features, suggests Aristotle, are those captured in the essence-specifying definitions used in science (again in the broad sense of epistêmê). 