Possession is possession. If you are in possession of stolen property you will be arrested.
Only if the authorities catch you.
Ownership is a legal definition.
Agreed.
Legal definitions are illusory.
A concept defined by a system that provides a mechanism to enforce your claim to property....as the law allows.
Should you and the authorities be in a position to enforce that claim-more to the point, should the law recognize that claim, regardless of what is right, legal or intended. Case in point: probate matters where real property is transferred to non-relatives, or people other than those the principle intended. Totally "legal ownership," transferred to those who celarly shouldn't have any claim at all, due to a "concept defined by a system that provides a mechanism to enforce your claim to property, as the law allows."
Again, "the law," is an illusion. Therefore, "ownership" is an illusion.....