All property rights are relative. Property rights are about excluding others from the use of the property in question. A world with a single inhabitant it unchanged whether that inhabitant is considered to own everything that exists or nothing that exists. So practical philosophy of property rights is not about determining who owns what, but rather of determining who has a better claim to ownership of what than whom. As far as I can tell, there are only two ‘obvious’ cases which we can determine directly, rather than derivative from other claims of ownership: self-ownership, each person has a better claim to their own body (reflected here in the language that vernacular English forces on me) than anyone else; and ownership of the commons, no person has any better claim to the commons than anyone else (though this is smuggling in the tricky bits under the term ‘commons’).
Property is about the right of access, not the right of exclusivity. Exclusivity is a derivative right that follows from the right to access rival goods; if I have a right to access a rival good, then your accessing that good infringes on my right to access that good. I have the right to control my body, because I own my body, and since at anyone point only a single entity can be in control of my body, since it is a singular thing, then my right must not be interfered with; other’s do not have any right to control my body. Rights are an expression of positive protection of an individual, they do not need to reference external parties, e.g. I have a right not be murdered, I do not have a right to you not murdering me except as a special case of that more general right. Note that exclusive intellectual ‘property rights’ cannot be worded in such a way; they must always reference external entities.