Psychological Egoism

Psychological egoism is the view that people are always selfish. When was the last time you did a good deed? Did you do it for its own sake, or for your own? The egoist says that all of us are necessarily self-regarding. I shall argue that this view is incorrect.
First we should ask, what kind of claim is this? Is it an a priori claim, or a generalization from experience? If it were the latter, we could never conclusively prove it: we could never show that necessarily all actions are selfish. So it must be a priori. But no a priori claim could be substantive: a priori truths are all analy…