Whether pleasure is the measure or rule by which to judge of moral good or evil?

❌ Objection 1 : It would seem that pleasure is not the measure or rule of moral good and evil. Because "that which is first in a genus is the measure of all the rest" (Metaph. x, 1). But pleasure is not the first thing in the moral genus, for it is preceded by love and desire. Therefore it is not the rule of goodness and malice in moral matters.

❌ Objection 2 : Further, a measure or rule should be uniform; hence that movement which is the most uniform, is the measure and rule of all movements (Metaph. x, 1). But pleasures are various and multiform: since some of them are good, and some evil. Therefore pleasure is not the measure and rule of morals.

❌ Objection 3 : Further, judgment of the effect from its cause is more certain than judgment of cause from effect. Now goodness or malice of operation is the cause of goodness or malice of pleasure: because "those pleasures are good which result from good operations, and those are evil which arise from evil operations," as stated in Ethic. x, 5. Therefore pleasures are not the rule and measure of moral goodness and malice.