The homestead principle is the principle by which one gains ownership of an unowned natural resource by performing an act of original appropriation. Appropriation could be enacted by putting an unowned resource to active use (as with using it to produce a product), joining it with previously acquired property or by marking it as owned (as with ). Proponents of intellectual property hold that ideas can also be homesteaded by originally creating a virtual or tangible representation of them. Others however argue that since tangible manifestations of a single idea will be present in many places, including within the minds of people, this precludes their being owned in most or all cases. Homesteading is one of the foundations of Rothbardian anarcho-capitalism.
Enlightenment philosopher John Locke in his work Second Treatise of Government, published in 1690 advocated the Lockean proviso, which allows for homesteading. Locke famously sees the "mixing of labour" with land as the source of ownership via homesteading. He writes:
Though the earth and all inferior creatures be common to all men, yet every man has a property in his own person. This nobody has any right to but himself. The labour of his body and the work of his hands, we may say, are properly his. Whatsoever, then, he removes out of the state that Nature hath provided and left it in, he hath mixed his labour with it, and joined to it something that is his own, and thereby makes it his property.
However, Locke held that individuals have a right to homestead private property from nature only so long as "there is enough, and as good, left in common for others". The Lockean proviso maintains that appropriation of unowned resources is a diminution of the rights of others to it, and would only be acceptable if it does not make anyone else worse off.