I have argued throughout that the origin of modern ideas about human nature lies not in the methods of investigation provided by psychoanalysis, phenomenology or semiotics but in the historical decline of Christianity, particularly in its hold over the intellectuals. My evidence for this is partly that we find like-minded thinkers like Nietzsche and Jaspers use different methods of investigation, while a single method of investigation, such as psychoanalysis, can produce thinkers as diverse as Freud, Jung and Lacan. On the more positive side clear links can be established between the contents of the doctrines of Nietzsche, Freud and Sartre and the historical decline of Christianity.