 But why does Hegel come to define reason in terms of dialectics, and hence adopt a dialectical method? We can begin to see what drove Hegel to adopt a dialectical method by returning once again to Plato’s philosophy. Plato argued that we can have knowledge of the world only by grasping the Forms, which are perfectly universal, rational concepts or ideas. Because things in the world are so imperfect, however, Plato concluded that the Forms are not in this world, but in a realm of their own. After all, if a human being were perfectly beautiful, for instance, then he or she would never become not-beautiful. But human beings change, get old, and die, and so can be, at best, imperfect copies of the Form of beauty—though they get whatever beauty they have by participating in that Form. Moreover, for Plato, things in the world are such imperfect copies that we cannot gain knowledge of the Forms by studying things in the world, but only through reason, that is, only by using our rationality to access the separate realm of the Forms (as Plato argued in the well-known parable of the cave; Republic, Book 7, 514–516b).