Ownership is just a social agreement, dude.

We literally made it up.

You never needed an institution.

You just needed a granddaughter who holds your fav hat, and even though it would look great on her, won't wear it because it's so intensely yours. Because wearing it would be like appropriation and admitting she'd never see you again and wronging you all at once.

Or a pen to write your name on it in the fucking fridge.

Or the understanding that you have put this in your mouth and used it to scrub goo off your bones and are likely to do so again in the future. Maybe an appreciation from those who live near you for the benefits of that scrubbing to their sense of smell.