As I understood as a term,
Speculative fiction is a term used not to differentiate, but to include all literature that takes place in a universe slightly different from our own. In essence it includes all the sub genres of both
science fiction and
fantasy, including
Hard SF,
Alternate History and
Sword and Sorcery. Writers from each sub-genres often cross over to the other in search of a good story.
David Brin's novel
The Practice Effect effectively straddles both disciplines as does
Ron Sarti's
The Chronicles of Scar.
Orson Scott Card once described the difference as being whether the writer chooses to use
spaceships and
aliens in his story, as opposed to
trees and
elves. Or vice versa.
Traditional sword and sorcery tends to romanticize elements of the Arthurian Legend, mythology and medieval chivalry. I enjoy much of the genre, but it looks to the past and often glosses over the less desirable disadvantages of those lives, such as serfdom. After all, somebody had to clean Lothlorien’s latrines!
I think this romantic view almost necessary to enjoying the literature. While many of us can be gripped by great ideas, the romance of warping through space or dining with Tom Bombadil is part of what draws us to the literature. We get to imagine ourselves doing great things, and/or exploring new, fresh worlds. In this literature we get to recapture the thrill of discovering our world. It also frees writers to pursue their own personal vision. It is hard to imagine Gene Wolfe's brilliant imagination flourishing within the mainstream, though some of his work, like Peace defies categorization.
Science fiction is much more a literature of ideas. Larry Niven once wrote that while contemporary literature centered on character studies, SF was oriented on characters acting to affect their world, rather than simply reacting to this. In essence, he referred to it as a literature of action rather than being.
But Speculative Fiction in all its forms gives authors the ability to ask relevant questions about our society in a way that would prove provocative in more mainstream forms. The alternate universe or civilization provides an emotional and intellectual distance that permits a more dispassionate thought process. Ursula K. LeGuin used her hermaphroditc Gethenians to explore gender in her masterpiece The Left Hand of Darkness. Brin turned "The Island of Dr. Moreau" on its head with his Uplift series of novels. JR Dunn's challenging Days of Cain presents the Holocaust as a horrific lesson necessary for human social evolution.
In the introduction to the religious section in his short story anthology, Maps in the Mirror, Card described SF as the last true bastion of religious literature. To paraphrase him, most contemporary religious fiction preaches to the converted, it shows people who discover God and all their problems go away. Or they sin and are wrathfully punished. This simplistic approach may please true believers, as it reifies their beliefs. But it doesn’t ask the more relevant questions, which concern the implications of faith. Faith can lead many to good works, but as we have seen with al-Quaeda its misapplication may lead to horrible violence. Card explored the dark side of faith in his novel Children of the Mind where the smartest person in the universe is trapped into self destructive behavior by her belief. For all her intellect, she cannot accept new data when it attacks her strongly held beliefs.
Speculative Fiction in all its forms is a literature of freedom, freedom for the author to lose the chains of conventional thought, and freedom for the reader to lose themselves in discovery