Conscience is the expression of the ego in the moral realm. To make a moral judgment and to act on it are basically selfish acts. It’s the self that sees through its own eyes and acts on its own knowledge of right and wrong. Or to put it another way, you can’t really be selfish if you can’t live with yourself. Rational Selfishness as Ayn Rand tried to define and advocate was limited to acts which benefited one’s self but caused no affirmative harm or inflicted a cost on another person.