Man can pervert them. Men do commit suicide; men do hate; men do fail to grow intellectually. The perversion provides further proof of the naturalness of these three great and basic drives within man. What we have written so far can be confirmed by any man. He need merely look within himself. Does he not fear death? Does he not want to love and be loved? Why is he reading this study except that he wants to know?
We are on ground that no philosopher or philosophy can challenge and no pretended revelation can call into doubt.
Much, much more here.