But now the question comes, What kind of knowledge or wisdom does Socrates mean as the greatest excellence? In contrast to the Sophists, who relied upon the sensations and impulses as wisdom, Socrates turned to that element which had been the decisive factor of the culture of the time. This was _insight_. The greatest excellence is insight. He who acts according to his feelings is not sure of his knowledge, but he who acts according to insight has the greatest excellence in the world. But Socrates restricts the meaning of knowledge still further. Not only is knowledge to Socrates insight, but it is _moral_ insight. For the problems in which he was interested were the problems of human life and principally the problem of self-examination. Thus we can translate the conventional formal statement of Socrates, viz., _Knowledge is virtue_, into this rather longer sentence, _Moral insight is the most excellent thing in the world_. For the first time in the history of thought philosophy is founded upon a moral postulate. =What the Socratic Ideal involves.= We have now examined the meaning of the formal statement of the Socratic ideal. A further question along this same line concerns what that ideal involves. 1. In the first place, to possess knowledge is to act righteously. Knowledge ＝ righteous conduct. Socrates does not mean that knowledge is merely the _condition_ of right conduct; he means that knowledge actually _constitutes_ moral conduct. The development of the reason is actually the same as the development of the will. Knowledge is virtue and virtue is knowledge. Vice is ignorance and ignorance is vice. To have an insight into the truth is the principle of living. Not only is deficient insight the cause of evil, but it is itself the greatest evil. Not only does a man act wrongly because he does not know the good, but not to know the good is the greatest wrong that can happen to him.