In the classic science-fiction film “2001”, the ship's computer, HAL, faces a dilemma. His instructions require him both to fulfil the ship's mission (investigating an artefact near Jupiter) and to keep the mission's true purpose secret from the ship's crew. To resolve the contradiction, he tries to kill the crew.
As robots become more autonomous, the notion of computer-controlled machines facing ethical decisions is moving out of the realm of science fiction and into the real world. Society needs to find ways to ensure that they are better equipped to make moral judgments than HAL was.