the.com/self interest
the invisible hand's favorite excuse and the only motive that never lies about itself.
means acting to benefit yourself, which economics assumes you always do and morality keeps arguing about.
from adam smith built modern economics on it in 1776, arguing the butcher feeds you not from kindness but from wanting your money — a line so useful it outlived everything else in the book.
smith's other bookhe also wrote a whole treatise on empathy
rational choice theoryassumes it, then can't explain tipping
game theoryproves pure self interest often makes everyone worse off
altruism debatebiologists argue it's just self interest in disguise