Artificial intelligence is a dream of mankind, but it is also an elusive one. Science has created machines that can emulate certain human thought processes at high speed, but these machines cannot really be said to think. In fiction, however, the problems involved can be solved, and robots have been presented in fiction which are very human in the way they think. However, even as human beings in the real world seek to develop machines that can think, it is also apparent that these same human beings fear such machines. In fiction, this is often addressed by the development of rules for the conduct of robots and androids, and yet often these rules can be bent quite far by the intelligent machines at which the rules are directed. Isaac Asimov created perhaps the most famous set of such rules in his Three Laws of robotics, logical rules that the author uses to show the concerns of humankind and the ways those concerns might be addressed. In the film Blade Runner, based on a story by Philip K. Dick, the rules are built into the machine itself, perhaps because the machine is organic, an android which lives by biological processes rather than as a set of man-made circuits. What the androids share with the robots is the essential truth that none of them are truly human because they were not born, though they can all be human in a philosophical sense because they can think and feel.
The three laws as set forth by Asimov are that 1) a robot may not injure a human being or allow a human being to come to harm, 2) a robot must carry out orders given to it by a human being unless those orders conflict with the First Law, and 3) a robot must protect its own existence if that does not conflict with the First or Second Law. The robots in Asimov's stories now that they are robots and accept that, even if they are not always accepted themselves--they were accepted when they could not talk: "Afterward, they became more human and opposition be...