Science fiction and fantasy

To me, fantasy and science fiction exist for very similar reasons. I almost feel that science fiction is a subcategory of fantasy. I say this because both deal with the, for lack of a better word, fantastic and/or the highly improbable.  Their purpose in our culture is to allow humans to ecsape. When watching a fantasy or science fiction film, we play a trick on our own minds. The harsh laws of reality are suspended and for the length of film, we are able to live vicariously through the characters on screen. Fantasy and science fiction films are a socially acceptable way for a person to reject reality by momentarily casting off the innate cyniscism that comes with being alive and entering a world of absoluetly endless possibilities. Film viewers are able to do this because the world they are viewing, the world of the film, is "just a story". And absolutely anything can happen in a story. Science fiction however allows for a very specific fanstasy to be fully realized. The fantasy of man conquering all. The definition of science fiction I most agree with is Theodore Sturgeon's, that sci-fi is built around humans, has a human problem and ultimately has is ultimately solved by human ingenuity.  With science fiction, we cleverly let ourselves build up our perception of human superiority. With science fiction, we let ourselves believe that our human race can ultimately overcome any obstacle in our way. Is this true? Probably not, but science fiction holds a special place in the hearts of humans because it unassumingly lets us believe that we can.