Johnny Depp dies and is reborn as a computer brain in Transcendence, the latest science-fiction thriller about artificial intelligence. Smart machines that may serve or dominate mankind are as old as Samuel Butler’s 1872 novel Erewhon, or Karel Capek’s 1920 play R.U.R. — and as recent as this week’s episode of The Simpsons, in which Dr. Frink revives the dead Homer as a chatty screensaver. They have also inhabited some of the finest SF movies, including Dark Star, Star Wars, Star Trek the Motion Picture, Alien, Blade Runner, The Terminator and RoboCop. The list is inspiring and nearly endless.