The labor theory of property is a theory of natural law that holds that property originally comes about by the exertion of labor upon natural resources. The theory has been used to justify the homestead principle, which holds that one may gain whole permanent ownership of an unowned natural resource by performing an act of original appropriation.

Two Treatises of Government is a work of political philosophy published anonymously in 1689 by John Locke. The First Treatise attacks patriarchalism in the form of sentence-by-sentence refutation of Robert Filmer's Patriarcha, while the Second Treatise outlines Locke's ideas for a more civilized society based on natural rights and contract theory. The book is a key foundational text in the theory of liberalism.