Kepler's laws of planetary motion of solar system body number "i" is, according to Newton's laws: where formula_72 is the mass of body "j", formula_73 is the distance between body "i" and body "j", formula_74 is the unit vector from body "i" towards body "j", and the vector summation is over all bodies in the world, besides "i" itself. In the special case where there are only two bodies in the world, Earth and Sun, the acceleration becomes which is the acceleration of the Kepler motion. So this Earth moves around the Sun according to Kepler's laws. If the two bodies in the world are
Three Laws of Robotics later wrote that he should not be praised for creating the Laws, because they are "obvious from the start, and everyone is aware of them subliminally. The Laws just never happened to be put into brief sentences until I managed to do the job. The Laws apply, as a matter of course, to every tool that human beings use", and "analogues of the Laws are implicit in the design of almost all tools, robotic or not": Asimov believed that, ideally, humans would also follow the Laws: Asimov's stories test his Three Laws in a wide variety of circumstances leading to