Homestead principle

Appropriation could be enacted by putting an unowned resource to active use (as with using it to produce some product[a]), joining it with previously acquired property, or by marking it as owned (as with livestock branding).

For, whatever some idly say to the contrary, no injury is done to any person when a thing is occupied that is available to all but belongs to no one; however, only that labor which a man performs in his own name and by virtue of which a new form or increase has been given to a thing grants him title to these fruits (Paragraph 52)[5].Libertarian philosopher and Austrian School economist Murray Rothbard argued that homesteading includes all the rights needed to engage in the homesteading action, including nuisance and pollution rights.

He writes: Rothbard interpreted the physical extent to which a homesteading act establishes ownership in terms of the relevant "technological unit", which is the minimal amount necessary for the practical use of the resource.

[6]Hungarian political philosopher Anthony de Jasay argued that a homesteader, having a claim prior to any other, must be prima facie considered the owner of the resource, in accordance with the principle "let ownership stand": Similarly to de-Jasay, Hans-Hermann Hoppe argues that the denial of the homesteading rule entails a performative contradiction.

For limits to ownership above land, an old principle in the law is ad coelum, meaning that property rights extend "to the sky" (and below the earth).