谢谢ling_yin_shi的详评。怎样定义科幻，人见人殊。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.