謝謝ling_yin_shi的詳評。怎樣定義科幻，人見人殊。Here's my view:

I am inclined to follow Isaac Asimov who said in 1975 that "science fiction can be defined as that branch of literature which deals with the reaction of human beings to changes in science and technology. " His celebrated short story "Nightfall" was and still is a milestone of science fiction. It is worth checking out.