An alternative point of view is that no deep a priori justification for the concept of ownership exists, other than that you own what you can actually defend as

An alternative point of view is that no deep a priori justification for the concept of ownership exists, other than that you own what you can actually defend as such, be it by force or by law. Under this point of view, it would be totally conceivable that you couldn't own the products of your mind but could those of your hands, if the law just said so.