In such a tale, as in the Phaedrus, various aspects of the Ideas were doubtless indicated to Plato's own mind, as the corresponding theological problems are to us. The immanence of things in the Ideas, or the partial separation of them, and the self-motion of the supreme Idea, are probably the forms in which he would have interpreted his own parable. He touches upon another question of great interest--the consciousness of evil--what in the Jewish Scriptures is called 'eating of the tree of the knowledge of good and evil.' At the end of the narrative, the Eleatic asks his companion whether this life of innocence, or that which men live at present, is the better of the two. He wants to distinguish between the mere animal life of innocence, the 'city of pigs,' as it is comically termed by Glaucon in the Republic, and the higher life of reason and philosophy. But as no one can determine the state of man in the world before the Fall, 'the question must remain unanswered.' Similar questions have occupied the minds of theologians in later ages; but they can hardly be said to have found an answer. Professor Campbell well observes, that the general spirit of the myth may be summed up in the words of the Lysis: 'If evil were to perish, should we hunger any more, or thirst any more, or have any similar sensations? Yet perhaps the question what will or will not be is a foolish one, for who can tell?' As in the Theaetetus, evil is supposed to continue,--here, as the consequence of a former state of the world, a sort of mephitic vapour exhaling from some ancient chaos,--there, as involved in the possibility of good, and incident to the mixed state of man.