You don't think progress goes in a straight line, do you? Do you recognize that it is an ascending, accelerating, maybe even exponential curve? It takes hell's own time to get started, but when it goes it goes like a bomb.

My old English buddy, John Rackham, wrote and told me what made science fiction different from all other kinds of literature - science fiction is written according to the science fiction method.

That's really what SF is all about, you know: the big reality that pervades the real world we live in: the reality of change. Science fiction is the very literature of change. In fact, it is the only such literature we have.

If you don't care about science enough to be interested in it on its own, you shouldn't try to write hard science fiction. You can write like Ray Bradbury and Harlan Ellison as much as you want.

When I sit down to the feast of life ... I'm so busy planning on how to pick up the check, and wondering what the other people think of me for paying it, and wondering if I have enough money in my pocket to pay the bill, that I don't get around to eating.

The science fiction method is dissection and reconstruction.

The future depicted in a good SF story ought to be in fact possible, or at least plausible. That means that the writer should be able to convince the reader (and himself) that the wonders he is describing really can come true... and that gets tricky when you take a good, hard look at the world around you.