Below are different types of identity. Find the one you are working with and read the information. Listed are different stories that may help guide you in finding a short story to read.
Some standard revelations of hidden identity have become Clichés through overuse. A protagonist may prove to be secretly a Robot, as in Philip K Dick‘s classic treatments “Impostor” (June 1953 Astounding) and “The Electric Ant” (October 1969 F&SF); an Alien, as in A E van Vogt‘s “Asylum” (May 1942 Astounding); or – very frequently – a Superman, as in van Vogt‘s The World of Ā (August-October 1945 Astounding; rev 1948; vt The World of Null-A 1953 dos), whose hero also suffers from partial Amnesia caused by a Memory Edit. Roger Zelazny deploys most of these shifts, accompanied by a lecture on the frailty of identity, in an early scene of Creatures of Light and Darkness (1969).
Criminal personalities are destroyed and therapeutically rebuilt in Alfred Bester‘s The Demolished Man (January-March 1952 Galaxy; 1953), Ralph Blum‘s The Simultaneous Man (1970) and Robert Silverberg‘s The Second Trip (1972); the latter’s plot turns on the partial survival of the “bad” identity. Outside the realm of Crime and Punishment, further recreated identities feature in James Blish‘s “A Work of Art” (July 1956 Science Fiction Stories as “Art-Work”; vt in Science Fiction Showcase, anth 1959, ed Mary Kornbluth), in which the musician Richard Strauss (1864-1949) is artificially and temporarily reincarnated in the body of a volunteer; and Marcel Theroux‘s Strange Bodies (2013), one of whose similarly (but more cruelly and involuntarily) recreated personalities is that of Samuel Johnson. Both tales lead the victims to a desolating awareness of not being real; of possessing the mannerisms but not the essence of their originals.
Some form of Cartesian duality, with identity somehow independent of the body that sustains it, is frequently assumed in sf – rationalizing the immortal-soul concept of most Religions. Clifford Simak‘s Way Station (June-August 1963 Galaxy as “Here Gather the Stars”; 1963), whose Matter Transmission is really Matter Duplication with travellers’ surplus (and lifeless) bodies left behind, posits a future scientific proof that identity is indivisible and follows the transmitted body. Eric Frank Russell‘s Sentinels from Space (November 1951 Startling as “The Star Watchers”; exp 1953; vt Sentinels of Space 1954 dos) rationalizes the soul as the mature energy-being of which our corporeal existence is merely the larval stage; Bob Shaw similarly imagines human survival in energy form as “egons” in The Palace of Eternity (1969) – leading in both cases to the possibility of purely rational Reincarnation
Identity and Freewill
Nigel Dennis‘s Cards of Identity (1955) is a dark comedy based on the notion that identity is fragile and that charlatans can impose new identities on their victims by sheer persuasiveness. Thomas M Disch‘s “The Asian Shore” (in Orbit 6, anth 1970, ed Damon Knight) charts the unexplained transformation of an American’s identity into that of an undistinguished Turk. Identity is directly modified by electrical or electromagnetic intervention in Vincent Harper‘s The Mortgage on the Brain (1905), in Jack Chalker‘s The Identity Matrix (1982) and – plausibly and unpleasantly – in Scott Bakker‘s Neuropath (2008). Greg Egan has written several disturbing explorations of the theme; these include “Learning to be Me” (July 1990 Interzone), which focuses in detail on the process of Upload, “Mister Volition” (October 1995 Interzone), which deconstructs the very concepts of identity and free will, and “Reasons to be Cheerful” (April 1997 Interzone), whose protagonist becomes able to program his own emotional states. Peter Watts‘s Blindsight (2006) draws extensively on neurological research to mount (as does the already-cited Neuropath) a strong attack on the comforting sense that identity and self-awareness are central or even useful to our existence. John Scalzi‘s The Ghost Brigades (2006) and The Last Colony (2007) feature an imperfectly Uplifted alien species which has been given intelligence but not self-awareness: in the second book they acquire a prosthetic sense of identity via brain/computer interfacing. A similar problem, here unsolved, afflicts the highly intelligent Robot Villain of Barrington J Bayley‘s The Rod of Light (1985).