In sf, this term for the successors of present-day humanity does not normally refer to products of "natural" Evolution – like, perhaps, H G Wells's influential vision of evolved future man with bulging brain and partly atrophied body in "The Man of the Year Million" (6 November 1893 Pall Mall Budget) – but to the results of our own or others' intervention via Technology (including techniques of Biology), Genetic Engineering, Nanotechnology, and so on.
In terms of bodily modification, the dividing line between human and posthuman is not easily drawn. The quaddies of Lois McMaster Bujold's Falling Free (December 1987-February 1988 Analog; 1988), adapted for free fall with additional hands in place of feet, clearly remain human; so, at least in their suburban personalities, do characters with bizarre fashion-prosthetics in John Sladek's Satire "The Last of the Whaleburgers" (in The Lunatics of Terra, coll 1984). More exotic posthuman changes, including Cyborg bodies equipped to operate in both free-fall and vacuum, are found in Dougal Dixon's extrapolative nonfiction Man After Man: An Anthropology of the Future (1990) and Justina Robson's Natural History (2003) – the latter including posthumans organically designed to be Spaceships, a step beyond the more traditional sf transfer of brains from human-born bodies into Cyborg ships as in Anne McCaffrey's The Ship Who Sang (coll of linked stories 1969) or Kevin O'Donnell's Mayflies (1979).
Posthumans inhabiting recognizably human bodies tend to be mental Supermen (which see) with vastly enhanced Intelligence; this may be conferred by Computer interfacing, as in a wide range of stories from Joan D Vinge's "Fireship" (December 1978 Analog) to John Meaney's To Hold Infinity (1998) and beyond. The posthuman mind may be a many-bodied gestalt, as in Theodore Sturgeon's More Than Human (fixup 1953), Frederik Pohl's and C M Kornbluth's Wolfbane (October-November Galaxy; 1959), and various human-membered Hive Minds as in Stephen Baxter's Xeelee Sequence novels Coalescent (2003) and Exultant (2004). The hundred-minded compact at the heart of Elly Bangs's Unity (2021) will save the planet if it can cohere. The titular posthumans of Walter Jon Williams's Aristoi (1992) – who oversee, not always benignly, a vast human galactic society – cultivate multiple personality aspects to share, as it were, the Posthuman Man's Burden. The evolutionary shaping of societies into habitats for posthumans implies a shaper in control, like the Secret Master of a Godgame, whose control over the narratives of simulated worlds can be seen as god-like. Techno-occultish models of the posthuman future (see Libertarian SF) almost always incorporate a copyright owner in charge of the new world, whose hand may occasionally be invisible.
Since the 1980s the most popular route to posthumanity has been to free oneself from the limitations of flesh (the parallel with the tenets of many Religions is sufficiently obvious) by Upload into an electronic existence where humans can at last meet their AIs on more or less equal terms and even, after a fashion, interbreed. A biological analogue of such upload appears in Greg Bear's Blood Music (June 1983 Analog; 1985). Greg Egan's Diaspora (1997) opens with a bravura description of the "natural" birth in such an environment of a new intelligence, described in terms which challenge the accompanying epithet "artificial".
Posthumanity is generally assumed to prevail, though often with exceptions who provide comprehensible viewpoint characters, in the perhaps indescribable aftermath of the Singularity (which see). Sometimes unreconstructed humans are pitted against an enclave or cabal of posthumans, as in Ken MacLeod's The Stone Canal (1996) and The Cassini Division (1998), whose seemingly inimical posthuman "fast-folk" inhabit Jupiter; or in Shane Dix's and Sean Williams's Geodesica sequence opening with Geodesica: Ascent (2005). A relevant anthology is Supermen: Tales of the Posthuman Future (anth 2002) edited by Gardner Dozois. [DRL]
see also: Continuum: Roleplaying in the Yet; Gary M Gibson; Sid Meier's Alpha Centauri; Transcendence.
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