to that effect. However, the robot did not shut down or explode; it simply refused to continue working until a more logical command was given. In some cases, presenting a computer or robot with such a contradiction would cause it to violently self-destruct. This occurs in several episodes of the original series of Star Trek (e.g. "I, Mudd", "Requiem for Methuselah", "The Return of the Archons" and "The Changeling"), as well as in the finale to Logan's Run. In the episode of the 1968 television series The Prisoner entitled "The General", Patrick McGoohan causes a supercomputer to explode by feeding it the question "Why?". Such depictions reflect common perceptions of real computers at the time, which usually lacked friendly user interfaces. Computers often responded to bad input with an error message on the same order of utility as "does not compute", although self-destruction was an unlikely result from bad inputs or insoluble problems fed into the computer. The concept of a "killer poke", however, refers to user input intended to induce hardware damage. (See also "Halt and Catch Fire".) Although not using the phrase "does not compute", the short story "Liar!" (1941) by Isaac Asimov is a striking early example of cognitive dissonance leading to a robot's self-destruction: that whether it lies, tells the truth or says nothing, it will cause humans injury, so being unable to avoid breaking Asimov's First Law of Robotics: "A robot may not harm a human being, or, through inaction, allow a human being to come to harm." This example is a more sophisticated treatment of cognitive dissonance leading to self-destruction than most examples from later television science fiction. Asimov explored the theme of AI cognitive dissonance at length in his robot stories. In the Doctor Who story "The Green Death", the Doctor attempts to put the computer BOSS, which claims to be infallible, out of action using the liar paradox. BOSS feigns suffering from confusion as he appears to try to resolve the paradox, but has in fact summoned security. By the 1990s, with the rise of personal computers and the graphical user interface, the public conception of computers became more friendly and sophisticated, and the image of the computer intelligence unable to respond gracefully to unexpected inputs has gradually faded away from fiction, though the phrase did show up in Star Wars: Episode I – The Phantom Menace as comic relief in 1999.