In a meandering discussion on MetaFilter I had occasion to note that, as a genre, science fiction is closely related to religious writing.
If science fiction grants the reader access to an alternate reality, so does religious writing. Both are most powerful where fantasy (infinite) and reality (finite) overlap. Both are self-conscious: science fiction asks the reader to contemplate reality as such, religion allows the believer to transcend reality as such. Both promise the comfort (or horror) of a self-contained and/or complete world; the totality of time and space.
If anything, science fiction is the religious impulse articulated in a modern context.