[_0ffh]

> How is this society mutually beneficial by definition

I wrote "voluntary social interactions [...] are by definition mutually beneficial". A voluntary interaction implies that all participants in the interaction have chosen to do so by their own free will. That implies that they value going through with the interaction higher than to forego the interaction. Hence, it benefits all of them.

> If you and I both claim to own some land and we can't come to an agreement, isn't it going to be decided with superior force?

That's merely a technical problem. A land register might be a solution.