 While Pufendorf acknowledges a kind of primitive community within family units, under the aegis of the father, he distinguishes this from positive communion in the sense of common ownership (Buckle 1991). Both this and private dominion, or property properly speaking, arise gradually with the proliferation and dispersion of family units, as humans and their needs multiply (DJN IV.4.12). For under such conditions it becomes necessary to distinguish mine from thine through certain exclusionary conventions, if quarrels are to be avoided. Typically (but optionally), humans agree to a right of first occupancy or direct use, limited by the proviso of actual utility and the ability to defend what is occupied (DJN IV.6.3) – though this does not suffice for ownership without consent. Some things like the open ocean may (or can) not be owned, and so peaceful navigation thereon “belongs to everyone and is free.” However, other kinds of exclusive restrictions, such as unequal trade relationships among nations, are permitted, and “that vaunted freedom of trade does not prevent a state from favoring its own citizens over outsiders” (DJN IV.5.9–10). Also, since property is a moral relationship rather than a physical quality, the same things may be subject to different types of overlapping ownership (DJN IV.4.2). Dominion need not be exclusive, and humans may grant others a perfect or imperfect right over their possessions. Indeed, they may be obligated to do so (DJN IV.8).