First possession theory of property
Encyclopedia
The "first possession" theory of property holds that ownership of something is justified simply by someone seizing it before someone else does. This contrasts with the labor theory of property
where something may become property only by applying productive labor to it, i.e. by making something out of the materials of nature.
Labor theory of property
The labor theory of property or labor theory of appropriation or labor theory of ownership is a natural law theory that holds that property originally comes about by the exertion of labor upon natural resources...
where something may become property only by applying productive labor to it, i.e. by making something out of the materials of nature.