Ideas

Thesis: Mind-Expanding SF Ideas
FTL
time travel
alternative universes
extraterrestrials
AI
immortality
future history
etc

Antithesis: SF Cliches
The same ideas after sf became a genre and literary ghetto.

Synthesis: Creative SF Authors
Poul Anderson, SM Stirling and others preserve sf mind-expansion by writing originally and creatively about familiar ideas. Stirling's The Peshawar Lancers is set in an alternative history. His Conquistador involves travel between alternative histories. If we have read these works, then it does not surprise us to learn either that the same author's first three Draka novels are set in yet another alternative history or that his fourth Draka novel again involves travel between alternative histories. Does it follow that these works are all the same and not worth reading? With some writers, it would mean precisely that.

However, when reading Drakon, we realize that, although the premise is familiar, everything else is, as Brian Aldiss wrote long ago:

"...a voice singing in a new universe."
-Brian Aldiss, Space, Time And Nathaniel (London, 1966), p. 159.