It is not grounded upon the constitution of man, but upon his actions.

Writers on jurisprudence have explained its origin in a manner that may satisfy every man of common understanding.
"The earth is given to men in common for the purposes of life, by the bounty of Heaven.

But to divide it, and appropriate one part of its produce to one, another part to another, must be the work of men who have power and understanding given them, by which every man may accommodate himself, WITHOUT HURT TO ANY OTHER.
"This common right of every man to what the earth produces, before it be occupied and appropriated by others, was, by ancient moralists, very properly compared to the right which every citizen had to the public theatre, where every man that came might occupy an empty seat, and thereby acquire a right to it while the entertainment lasted; but no man had a right to dispossess another.
"The earth is a great theatre, furnished by the Almighty, with perfect wisdom and goodness, for the entertainment and employment of all mankind.

Here every man has a right to accommodate himself as a spectator, and to perform his part as an actor; but without hurt to others." Consequences of Reid's doctrine.
1.

That the portion which each one appropriates may wrong no one, it must be equal to the quotient of the total amount of property to be shared, divided by the number of those who are to share it; 2.