I don't want to justify religion in terms of its benefits to us. I believe that, on balance, it does a lot of bad things, too - a tremendous amount. But I don't think that the final justification of religion is the good it does for people. I think the final justification is that it's true, and truth takes priority over consequences. Religion helps us deal with what is most important to the human spirit: values, meaning, purpose, and quality.
