I've been reading Freud's The Future of an Illusion, where Freud makes the case that religion is a form of "wish fulfillment." Freud writes that for the individual “life is hard to bear,” and beyond this there is “the painful riddle of death, against which no medicine has yet been found.” And so to “make helplessness tolerable” man invents God and religion not because they are true but because we wish them to be true. “ For Freud, one may say, Christianity is adult Disneyland. We forget that Freud is the author of this portrait of religion that is widely espoused in our time.
Well, let's examine this Freudian explanation in an entirely secular and rational way. Imagine a bunch of people who have gathered in a room because they want to avoid life's difficulties--sickness, suffering, death--by making up a religion that will make them feel better. I can entirely see how such a group would come up with the concept of heaven. Heaven is a place where there is no suffering and no death. Eternal bliss would surely fit into my wish-fulfillment scheme.
But I don't see why this group would come up with the concept of hell. (We are not talking about why priests might later use the concept to enforce doctrinal obedience or institutional loyalty. We are talking about why wish-fulfilling humans would invent the concept in the first place.) Hell is not only worse than sickness but also worse than death, because death is merely the end, while hell implies eternal separation from God.
I also don't see why seekers of wish-fulfillment would come up with Christian morality. Who needs the Ten Commandments or other such rules which make our lives more difficult by asserting a series of "Thou Shall Nots"? Even Christians recoil from the severe demands of their ethical code. Recall the church father Augustine, who kept putting off his conversion to Christianity, praying to God, “Make me chaste, O Lord, but not yet.” In other words, a project of wish-fulfillment would seem to dictate a much more libertine social morality than the one we find in the Old and New Testaments.
Bottom line: Judaism and Christianity, not to mention the other great religions, hardly look like they are the product of mere wishful thinking. In fact, they posit a God and a moral universe that makes some fairly stern demands on humans. It's almost wishful to think that God does not exist, so that we can escape those demands. This is a point that does not seem to have occurred to poor Sigmund Freud.