ethical egoism: AIR if it maximizes one's (my) BEST interests.
BEST = conducive to self-preservation in society (i.e., playing by the mns of society).
want to see the force of BEST? not everything I consider my interest is in my BEST interest.
ex. having sex with a person I just met vs. being faithful to my girlfriend. my BEST interest is creating behavioral dispositions of fidelity towards my girlfriend. Why? It's good to keep my relationship healthy, but even more important for the egoist, it develops behaviors of self-governance that I need for life in general.
BEST also means playing by the rules of society. a very important rule is tit-for-tat, which translates as BENEVOLENCE (doing good).* The egoist tries to maximize her relationships in the world by being benevolent (whenever permitted) to increase her chances of success in the world. Why?
The more good she does, the more good is owed to her. You reap what you sow, is her lemma.
So, an egoist ends up being altruistic. But she is not fooling herself that altruism should erase the expecting good in return, why not? because that reinforces the stereotype of the free rider. I don't care how altruistic you appear, you don't want a friend that doesn't reciprocate the good you do for her (if you do, you are a self-destructive masochist).
Egoism has a slant for instrumentalizing people, i.e., treating people as means to her ends (we'll see the problem this presents when we study Kant's deontology).