I believe that man is the product of natural evolution; that he is part of nature and yet transcends it, being endowed with reason and self-awareness. ― (1962a: Beyond the Chains of Illusion. My Encounter with Marx and Freud (Credo Perspectives, planned and edited by Ruth Nanda Anshen), New York (Simon and Schuster) 1962, p. 174.)
The human species can be defined as the primate who emerged at the point of evolution where instinctive determination had reached a minimum and the development of the brain a maximum. This combination of minimal instinctive determination and maximal brain development had never occurred before in animal evolution and constitutes, biologically speaking, a completely new phenomenon. ― Lacking the capacity to act by the command of instincts while possessing the capacity for self-awareness, reason, and imagination―new qualities that go beyond the capacity for instrumental thinking of even the cleverest primates―the human species needed a frame of orientation and an object of devotion in order to survive. ― (1976a: To Have Or to Be?, New York (Harper and Row) 1976, p. 137.)