doppelganger (n.) Look up doppelganger at Dictionary.com
1830, from German Doppelgänger, literally "double-goer," originally with a ghostly sense. See double + gang (n.). Sometimes half-Englished as doubleganger.
kinetic (adj.) Look up kinetic at Dictionary.com
"relating to muscular motion," 1841, from Greek kinetikos "moving, putting in motion," from kinetos "moved," verbal adjective of kinein "to move" (see cite).
Buster Keaton's subject was kinetic man, a being he approached with the almost metaphysical awe we reserve for a Doppelgänger. This being was, eerily, himself, played by himself, then later in a projection room, watched by himself: an experience never possible to any generation of actors in the previous history of the world. [Hugh Kenner, "The Counterfeiters," 1968]
From 1855 as "causing motion." Related: Kinetical; kinetically.