Page "Three Laws of Robotics" Paragraph 16

In his short story " Evidence " Asimov lets his recurring character Dr. Susan Calvin expound a moral basis behind the Three Laws.

Calvin points out that human beings are typically expected to refrain from harming other human beings ( except in times of extreme duress like war, or to save a greater number ) and this is equivalent to a robot's First Law.

Likewise, according to Calvin, society expects individuals to obey instructions from recognized authorities such as doctors, teachers and so forth which equals the Second Law of Robotics.

Finally humans are typically expected to avoid harming themselves which is the Third Law for a robot.