That's a great example. At that point, it's up to the family and the son to negotiate what's acceptable. Ultimately, whatever arrangement they choose, the famil

That's a great example. At that point, it's up to the family and the son to negotiate what's acceptable. Ultimately, whatever arrangement they choose, the family unit benefits. I think where this analogy breaks down and becomes gray area in modern society is when the group unit that benefits gets too large to ascertain where the gains are accruing. We're biologically wired to optimally deal with groups of ~150 or fewer people.