I repeat Sturgeon's Revelation, which was wrung out of me after twenty years of wearying defense of science fiction against attacks of people who used the worst examples of the field for ammunition, and whose conclusion was that ninety percent of it is crud. The Revelation: Ninety percent of everything is crud. Corollary 1: The existence of immense quantities of trash in science fiction is admitted and it is regrettable; but it is no more unnatural than the existence of trash anywhere. Corollary 2: The best science fiction is as good as the best fiction in any field.

That Heel. That lousy wart on the nose of progress.

Interview with David G Hartwell, The New York Review of Science Fiction (March - April 1989)

It's the Simple things that are really effective. Try to remember that.

But can we go to posterity with a sheaf of loose pages, or ask the readers of those days, with the whole of literature before them, to sift our enormous rubbis…

[F]olks would better off dipping their heads in a bucket of liquid [nitrogen] and battering them against a tree very very hard than reading Baxter's Titan. It …

His poetry, as a whole, is more nearly the real right thing than any of the poetry of a somewhat older generation than mine except Mr. Yeats's.