Rules of ownership are necessary for rivalrous goods, and not for others. Citing Thomas Jefferson,

"He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper [(candle)] at mine, receives light without darkening me.

That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density in any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation."