"Contrary to the prevalent image of the egoist as oblivious to all standards and moved entirely by what he wants, when he wants it, [Ayn] Rand sees such an erratic, emotion-driven course as a sure way to sabotage one's well-being. Serving one's interest requires action guided by the recognition of certain constant, fundamental facts. These facts are the basis of moral principles."
January 1, 1970
https://en.wikiquote.org/wiki/Ayn_Rand