The rational egoist constantly seeks to grasp the value-implications of the things and conditions around him—i. e., whether they may be good or bad for his or her life. Over time, these repeated evaluations are assimilated into the subconscious, giving rise to often passionate emotional responses. (The origins of such responses were investigated in pp. 1.3:84-8.) Aside from certain special situations (pp. 1.3:89-91), however, the egoist's principal cognitive tool is not emotion but reason. Each new situation must be examined dispassionately, setting emotional prejudices aside. Having determined the right course of action, on the other hand, the egoist is able to channel strong emotional energies to the task.

Rationality does not entail (as some of its detractors believe) adhering consistently to a theory in the face of contradictory evidence. On the contrary, such behavior is the epitome of irrationality! For the rational egoist, there are no evil thoughts, but it would be an unconscionable evil to cling to a belief that cannot be justified by the evidence—or to a policy known to be fundamentally destructive to human life.