Socrates, here, adopts Plato's theory of Forms, and introduces two faculties of the mind: (1) knowledge of the real and (2) belief in appearances. If, for example, a man can understand the nature of the ideal Forms, then he can be said to understand, through his reason, the true nature of a given Form, for example, Beauty. In this case, the philosopher has achieved knowledge of Beauty. But if another man sees that some things are beautiful, then, from his point of view, he is said to possess a belief in the appearance of Beauty in the thing he perceives to be beautiful. Another example of the distinction (an intellectual, logical distinction) that Socrates is making is Ugliness. A person who is a philosopher can come to the knowledge of ideal Ugliness; a person who sees some things as being ugly by definition believes in the appearance of Ugliness. The philosopher, the lover of truth, is a knower of the truth. The person who, for whatever cause, cannot be a philosopher is one who understands only a belief in the appearance of things. For Plato, a Form such as Beauty and a Form such as Ugliness are mutually exclusive; the Forms exist inherently in and of themselves. True Beauty can never be ugly; true Ugliness can never be beautiful. Forms (Beauty and/or Ugliness, for example) are never-changing; they are timeless. Of course some men may disagree about whether a thing is beautiful or ugly, but their disagreement is predicated upon their points of view; both men are believers in appearance. Again, we are reminded, the philosopher possesses knowledge of the real; the non-philosopher possesses only belief in appearance.
Another way of perceiving the distinction between the philosopher and the non-philosopher is to say that the philosopher is wide awake; the non-philosopher lives in a kind of dream world. Only the philosopher can understand the Truth and love it as the Truth. This apprehension of Truth involves a knowledge of the Forms, which are singular and ideal, and which do exist; whether or not we are able to perceive them, the Forms are real. Men who do not see the reality of a form, such as Beauty, but who call things in the day-to-day world beautiful are reacting only to images or reflections of the Forms.
