In the beginning of the movie I, Robot, a robot has to decide whom to save after two cars plunge into the water—Del Spooner or a child. Even though Spooner screams "Save her! Save her! " the robot rescues him because it calculates that he has a 45 percent chance of survival compared to Sarah’s 11 percent. The robots decision and its calculated approach raise an important question: would humans make the same choice? And which choice would we want our robotic counterparts to make? Isaac Asimov evaded the whole notion of morality in devising his three laws of robotics, which hold that 1. Robots cannot harm humans or allow humans to come to harm; 2. Robots must obey humans, except where the order would conflict with law 1; and 3. Robots must act in self-preservation, unless doing so conflicts with laws 1 or 2. These laws are programmed into Asimov's robots—they don't have to think, judge, or value. They don't have to like humans or believe that hurting them is wrong or bad. They simply don't do it. The robot who rescues Spooners life in I, Robot follows Asimovs zero law: robots cannot harm humanity (as opposed to individual humans) or allow humanity to come to harm—an expansion of the first law that allows robots to determine what's in the greater good. Under the first law, a robot could not harm a dangerous gunman, but under the zero law, a robot could kill the gunman to save others. Whether it's possible to program a robot with safeguards such as Asimov’s laws is debatable. A word such as "harm "is vague (what about emotional harm? Is replacing a human employee harm?), and abstract concepts present coding problems. The robots in Asimov’s fiction expose complications and loopholes in the three laws, and even when the laws work, robots still have to assess situations. Assessing situations can be complicated. A robot has to identify the players, conditions, and possible outcomes for various scenarios. It's doubtful that a computer program can do that—at least, not without some undesirable results. A roboticist at the Bristol Robotics Laboratory programmed a robot to save human proxies ( 替身 ) called “H-bots” from danger. When one H-bot headed for danger, the robot successfully pushed it out of the way. But when two H-bots became imperiled, the robot choked 42 percent of the time, unable to decide which to save and letting them both "die." The experiment highlights the importance of morality: without it, how can a robot decide whom to save or what's best for humanity, especially if it can't calculate survival odds?