"Self interest" doesn't imply rationality, it just means that people generally do what they want to do, for their own goals. Adam Smith never claims that people

"Self interest" doesn't imply rationality, it just means that people generally do what they want to do, for their own goals. Adam Smith never claims that people's goals make rational sense. The efficient market hypothesis is a 20th century invention. "Homo economicus" is a 19th century invention. Smith's interests were philosophical, not economical. His biggest contribution was the observation that self interest is a force for net social gain, because every person pursuing their own interests leads to greater prosperity for all. Hence his famous quote: "It is not from the benevolence of the butcher, the brewer, or the baker, that we expect our dinner, but from their regard to their own interest. We address ourselves, not to their humanity but to their self-love, and never talk to them of our necessities but of their advantages."