Henry Sidgwick quotes:

I do not see why the axiom of Prudence should not be questioned, when it conflicts with present inclination, on a ground similar to that on which Egoists refuse to admit the axiom of Rational Benevolence. If the Utilitarian has to answer the question, 'Why should I sacrifice my own happiness for the greater happiness of another?' it must surely be admissible to ask the Egoist 'Why should I sacrifice a present pleasure for a greater one in the future? Why should I concern myself about my own future feelings any more than about the feelings of other persons?'

Reason shows me that if my happiness is desirable and good, the equal happiness of any other person must be equally desirable.

Society is like a schoolmaster who estimates boys according to their conformity to a standard that is easiest for running a school.

We think so because all other people think so; Or because-or because-after all, we do think so; Or because we were told so, and think we must think so; Or because we once thought so, and think we still think so; Or because, having thought so, we think we will think so.