A claim of “This is mine!” is not the end of property. If it were, then property would be as purely subjective as “I want this” is. Rather, property requires that people other than me also know the circumstances of when my claim of “Mine!” is indeed true.
Property is a rather old subject. We’ve been writing about it since at least the time of the Sumerian tablets, in part, because after four and a half millennia we still haven’t settled on what property is, who has it, how we get it, or even what it’s for.