Although men may sometimes take a God’s eye view of the universe, they cannot consistently think of themselves as not being covered by any universal account they give of the world or of humanity. For they are men, and live in the world. It is a fair criticism of many philosophies, and not only determinism, that they are hoist with their own petard. The Marxist who says that all ideologies have no independent validity and merely reflect the class interests of those who hold them can be told that in that case his Marxist views merely express the economic interests of his class, and have no more claim to be adjudged true or valid than any other views. So too the Freudian, if he makes out that everybody else’s philosophy is merely the consequence of childhood experiences, is, by parity of reasoning, revealing merely his delayed response to what happened to him when he was a child. So too the determinist. If what he says is true, he says it merely as the result of his heredity and environment, and nothing else.
John Lucas, The Freedom of the Will, Oxford, 1970, p. 114