In the seventh grade I nearly got into a knock-down, drag out fight with my best friend. He was a fantasy fan, and I thought SF ruled. To an seventh grader, it looked like the end of the world!

The Starcraft Analysis thread got me thinking again...
I''ve always wondered if there''s a genre bridge between the two, something that could draw in and not repel or offend fans of each. I don''t think it''s science-fantasy, as swords and spells turn everything into fantasy with a SF setting.
If you like fantasy, what''s essential about it, without which it wouldn''t be good fantasy for you? Could SF duplicate it?
If you like SF, what''s essential about SF, without which it would suck? Could fantasy have these elements?
For me, a fantasy world that has understandable rules, with some internal consistency and believability, works just fine (absent stereotypical plot and such). As an SF fan, I want structure. If the rules change, just because the Gods will or it''s Friday, I go nuts and put the book down. As a game world, Thief mostly works for me because of this, as does Age of Empires (really history, not fantasy... but still).
I think a good cross-over might be a relatively low-tech society on a strangely alien environment, where psionics form a kind of magic... or an extremely high tech background modeled on some type of mythology, where technology IS magic, like the book Lord of Light (where some colonists have used technology to turn themselves into Hindu gods, and driven out the world''s energy based Rakasha "demons")
Can we all get along???

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Just waiting for the mothership...