I think in order to write The selfish Gene it required Hamilton.
We realize that, sick or healthy, George is a selfish, bitter jerk.
I'm amazed, as quirky, individual and selfish as most of us are, that anyone stays married for long.
Let us understand what our own selfish genes are up to, because we may then at least have the chance to upset their designs. [Richard Dawkins, "The Selfish Gene," 1976]Related: Selfishly; selfishness. Cf. similar formations in German selbstisch, Swedish sjelfvisk, Danish selvisk.