1. As to the Faculty of discerning Right. This is implied in the foregoing statement of the criterion. It is the Cognitive or Intellectual power. In the definite position taken up in Protagoras, it is the faculty of Measuring pleasures against one another and against pains. In other dialogues, measure is still the important aspect of the process, although the things to be measured are not given.
2. As regards the Will. The theory that vice, if not the result of ignorance, is a form of madness, an uncontrollable fury, a mental distemper, gives a peculiar rendering of the nature of man's Will. It is a kind of Necessity, not exactly corresponding, however, with the modern doctrine of that name.
3. Disinterested Sentiment is not directly and plainly recognized by Plato. His highest virtue is self-regarding; a concern for the Health of the Soul.
III.—On the Bonum, or Summum Bonum, Plato is ascetic and self-denying. 1. We have seen that in Philebus, Pleasure is not good, unless united with Knowledge or Intelligence; and the greater the Intelligence, the higher the pleasure. That the highest happiness of man is the pursuit of truth or Philosophy, was common to Plato and to Aristotle.
2. Happiness is attainable only through Justice or Virtue. Justice is declared to be happiness, first, in itself, and secondly, in its consequences. Such is the importance attached to this maxim as a safeguard of Society, that, whether true or not, it is to be maintained by state authority.
3. The Psychology of Pleasure and Pain is given at length in the Philebus.
IV.—With regard to the scheme of Duty. In Plato, we find the first statement of the four Cardinal Virtues.
As to the Substance of the Moral Code, the references above made to the Republic and the Laws will show in what points his views differed from modern Ethics.
Benevolence was not one of the Cardinal Virtues.
His notions even of Reciprocity were rendered hazy and indistinct by his theory of Justice as an end in itself.