It's clear that science and science fiction have overlapping populations.

Science fiction is the very literature of change.

My first thought was always a cigarette. It still is, but I haven't cheated.

I did that for 40 years or more. I never had any writer's block. I got up in the morning, sat down at the typewriter - now, computer - lit up a cigarette.

A good science fiction story should be able to predict not the automobile but the traffic jam.

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.

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.