Axiom of Equity
The Axiom of Equity was proposed by Samuel Clarke (1675 - 1729), an English philosopher, in the spirit of the ethic of reciprocity. In his book "A Discourse Concerning the Unchangeable Obligations of Natural Religion, and the Truth and Certainty of the Christian Revelation", Clarke wrote:
Whatever I judge reasonable or unreasonable for another to do to me; that, by the same judgment, I declare reasonable or unreasonable, that I in the like case should do for him.
One man's good is of as much intrinsic worth as the like good of another.