Other psychic factors being equal, it is to everyone's self-interest to maximize his monetary income on the market. But this maximum income can then be used for either “selfish” or for “altruistic” ends.
Income can never be equal. Income must be considered, of course, in real and not in money terms; otherwise there would be no true equality. We publish this in honor of what would have been Murray Rothbard's 97th birthday.