SF and F are grouped together because they are speculative - they answer the question 'what if?' - which horror can also do, and that's why it is already frequently grouped with them. But SF is not fundamentally more rooted in facts than fantasy. That's a mistake along the same lines as supposing fantasy can't be realistic simply because it contains the fantastic. SF's questions are rooted in science, but it's every bit as capable of becoming divorced from facts.>