According to
Isaac Asimov, "Science fiction can be defined as that branch of literature which deals with the reaction of human beings to changes in
science and
technology."
Robert A. Heinlein wrote that "A handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the
scientific method."