I will define science fiction, first, by saying what sf is not. It cannot be defined as “a story (or novel or play) set in the future,” since there exists such a thing as space adventure, which is set in the future but is not sf: it is just that: adventures, fights and wars in the future in space involving super-advanced technology. Why, then, is it not science fiction? It would seem to be, and Doris Lessing (e.g.) supposes that it is. However, space adventure lacks the distinct new idea that is the essential ingredient. Also, there can be science fiction set in the present: the alternate world story or novel. So if we separate sf from the future and also from ultra-advanced technology, what then do we have that can be called sf?

We have a fictitious world; that is the first step: it is a society that does not in fact exist, but is predicated on our known society; that is, our known society acts as a jumping-off point for it; the society advances out of our own in some way, perhaps orthogonally, as with the alternate world story or novel. It is our world dislocated by some kind of mental effort on the part of the author, our world transformed into that which it is not or not yet. This world must differ from the given in at least one way, and this one way must be sufficient to give rise to events that could not occur in our society—or in any known society present or past. There must be a coherent idea involved in this dislocation; that is, the dislocation must be a conceptual one, not merely a trivial or bizarre one—this is the essence of science fiction, the conceptual dislocation within the society so that as a result a new society is generated in the author’s mind, transferred to paper, and from paper it occurs as a convulsive shock in the reader’s mind, the shock of dysrecognition. He knows that it is not his actual world that he is reading about.