That's not a Tragedy of the Commons. Tragedy of the Commons is what happens when nobody clearly owns something that many people use, so none of them use it responsibly. That's not relevant at all to people hoarding their own wealth.

> That's not a Tragedy of the Commons.

GPs example is exactly game-theoretix tragedy of the commons / prisoners dilemma.

> Tragedy of the Commons is what happens when nobody clearly owns something that many people use, so none of them use it responsibly.

It's specifically, originally, a term for overgrazing a pastureland resulting from the kind of arrangement you described; there are a number of generalizations from that example which have been given the name, including both the one you describe, and the even more general condition in which each player has a dominant strategy of defection even though all players cooperating has a better payoff than all defecting.

The fact that Tragedy of the Commons is a subset of game theory defection problems does not change the fact that its defining requirement is the existence of a "Commons."

The Commons need not be an overgrazed pastureland; it can be any open access resource. The best modern example would be Earth's atmosphere and how its being filled with pollution. GGP has not specified a Commons and the existence of one is not implied in his comment.

> The fact that Tragedy of the Commons is a subset of game theory defection problems does not change the fact that its defining requirement is the existence of a "Commons."

The fact that the term has long been widely accepted as a label for the general class of problems, OTOH, does.

(Arguably, the structure of the payoff matrix in the class of problems implies an economically real if intangible “commons” in any problem in the class, which is probably why the label is used that way.)

Ok, what is the Commons he is talking about?

Presumably the 'Commons' here is control over the government. However, the example is a trivialization of reality and that matters, in the same way that assuming all economic actors are rational matters (they aren't). It's fun when we can use simple laws of nature to make predictions accurately. Unfortunately, it doesn't work in the field of economics\politics almost ever.

You didn't mention the effect of the poor who are now richer getting more power. You didn't mention that people can gain power by being virtuous and admirable, in fact damaging your own interests on purpose is a direct sign of power. Signalling is not a new concept.

The overall effect is more uncertain than you suggest, but presumably it's clear that the 'giving' that is highly desired and publicly demanded by certain people can be implemented by them today.

Further, I'd postulate that the desire to only give if everyone gives is a rather convenient mechanism to simultaneously not give and appear virtuous.