This is a quote from the book "The Virtue Of Selfishness" by Ayn Rand
...o choice about it, and he has no choice about the standard that determines what will make him experience the physical sensation of pleasure or of pain. What is that standard? His life.
read full book
r /> The pleasure-pain mechanism in the body of man — and in the bodies of all the living organisms that possess the faculty of consciousness — serves as an automatic guardian of the organis
m’s life. The physical sensation of pleasure is a signal indicating that the organism is pursuing the right course of action. The physical sensation of pain is a warning signal of danger, indi...