Freud argued that religious belief is an illusion. And he meant this in a precise sense: a belief is an illusion if it is derived from human wishes. Illusions are by their very nature misleading. For people take their beliefs to be responsive to the way things are. So if a belief is held in place by wishes, people are misled about their orientation to the world. Beliefs can be true or false; the same holds for illusions. It is not out of the question for an illusion to be true. The essential problem for an illusion, then, is that we are mistaken about the basis of our commitment to it. We take it to be a belief based on the responsiveness to the world; in fact, it is held in place by primordial wishes of which we are unconscious.
Freud’s argument is oblique. He does not address religion directly; and ostensibly he makes no claims about whether religious beliefs are illusions. That is, whatever the truth of religious claims, the fact that we believe them is not based on that truth, but rather on infantile wishes. His expectations seems to be that once we recognize these beliefs as illusions, and come to see the kind of wishes they gratify, the temptation towards religious belief will fall away. At the very least, we will see that we ought to give up religious belief.
Jonathan Lear – Freud p.203