Dave Truesdale’s gone “Off on a Tangent” again:

The Oddball, the Whacky, and the Prophetic in Short SF

From April, 1926 to . . . now?

SF, taken as an official genre and in the broadest sense, has never consciously set out to “predict” the future. Yes, there are exceptions, but they only prove the rule. That it has on occasion happened to do so in its 80+ years of official existence as a genre–April, 2006 marking its 80th year–merely happens to be a sideline plus. But it gave rise to the mistaken notion in its earlier days (after the public began to take notice of our new literature) that this was the primary (if not the only) purpose of SF, and the field was thus defined by many in the general public and the press solely on this basis; as a predictive literature. This popular and long-standing notion still exists among a very few of the unenlightened. Actually, more often than not and truth be told, the imaginative SF writer threw many inventive, creative, wild ideas against the wall–in the service of story–and a few of them, down through the years, have stuck (i.e. have come to pass).

Go read it and then argue with him about it.