Charles Sanders Pierce devised a way out of the problems raised by metaphysics that he called pragmatism. He formulated it in different ways over years, one of which is this:
To ascertain the meaning of an intellectual conception one should consider what practical consequences might result from the truth of that conception—and the sum of these consequences constitute the entire meaning of the conception.
William James, the psychologist brother of novelist Henry James, advocated pragmatism as well and elements of pragmatism are still found in contemporary philosophy. James held a pragmatist theory of truth—that truth is simply what is useful to believe. James carried this into the subject of religion and in his book, The Varieties of Religious Experience, he ridicules the position of Kant:
Immanuel Kant held a curious doctrine about such objects of belief as God, the design of creation, the soul, its freedom, and the life hereafter. These things, he said, are properly not objects of knowledge at all. Our conceptions always require a sense-content to work with, and as the “soul," "God," "immortality," cover no distinctive sense-content whatever, it follows that theoretically speaking they are words devoid of any significance. Yet strangely enough they have a definite meaning for our practice. We can act as if there were a God; feel as if we were free; consider Nature as if she were full of special designs; lay plans as if we were to be immortal; and we find then that these words do make a genuine difference in our moral life. Our faith that these unintelligible objects actually exist proves thus to be a full equivalent in praktischer Hinsicht, as Kant calls it, or from the point of view of our action, for a knowledge of what they might be, in case we were permitted positively to conceive them. So we have the strange phenomenon, as Kant assures us, of a mind believing with all its strength in the real presence of a set of things of no one of which it can form any notion whatsoever.
The Roman poet Ovid put it more succinctly: "Since it is useful to believe there are gods, let us believe there are."
We all rely on pragmatic notions in everyday life whether or not we call them true, but it does not seem a good way to conduct philosophy or science since. It leads directly to the notion of subjective truth. I wonder if theists are happy with the idea that believing in God and acting "as if" a god exists are really the exact same thing.
Allan, I think Karl Rove was being a pragmatic philosopher on the last presidential election day. He kept insisting What's-his-name - the rich guy - was winning. He looked like he was believing really hard.
Kind of reminds be about having to really believe in fairies to save Tinker Bell.