The PHILEBUS has a decidedly ethical character. It propounds for enquiry the _Good_, the Summum Bonum. This is denied to be mere pleasure, and the denial is enforced by Sokrates challenging his opponent to choose the lot of an ecstatic oyster. As usual, good must be related to Intelligence; and the Dialogue gives a long disquisition upon the One and the Many, the Theory of Ideas, the Determinate and the Indeterminate. Good is a compound of Pleasure and Intelligence, the last predominating. Pleasure is the Indeterminate, requiring the Determinate (Knowledge) to regulate it. This is merely another expression for the doctrine of Measure, and for the common saying, that the Passions must be controlled by Reason. There is, also, in the dialogue, a good deal on the Psychology of Pleasure and Pain. Pleasure is the fundamental harmony of the system; Pain its disturbance. Bodily Pleasure pre-supposes pain [true only of some pleasures]. Mental pleasures may be without previous pain, and are therefore pure pleasures. A life of Intelligence is conceivable without either pain or pleasure; this is the choice of the Wise man, and is the nature of the gods. Desire is a mixed state, and comprehends body and mind. Much stress is laid on the moderate and tranquil pleasures; the intense pleasures, coveted by mankind, belong to a distempered rather than a healthy state; they are false and delusive. Pleasure is, by its nature, a change or transition, and cannot be a supreme end. The mixture of Pleasure and Intelligence is to be adjusted by the all-important principle of Measure or Proportion, which connects the Good with the Beautiful. A decided asceticism is the ethical tendency of this dialogue. It is markedly opposed to the view of the Protagoras. Still greater is the opposition between it and the two Erotic dialogues, Phaedrus and Symposium, where _Bonum_ and _Pulchrum_ are attained in the pursuit of an ecstatic and overwhelming personal affection.