Freud's claim that psychoanalysis is a science and not a philosophy was objectively motivated by a need to defend it against charges of being unscientific and mystical. Slochower contends that it was also a defense against his own buried desire to see and be united with his preoedipal and oedipal mother. The author's central argument is, "In his longing for philosophic knowledge, as in his longing for mother, Freud faced questions of beginnings and ends, of life and death, of Eros and Thanatos."