I can’t possibly be the first person to think of this one …
The very phrase ‘tragedy of the commons’ is a reference to the prototypical example of such a tragedy: sheep grazing on common pasture land. The idea is that when the pasture (the “commons”) is owned collectively, then each peasant has an incentive to graze more than his fair share of sheep. The incremental drop-off in the quality of the pasturage is borne by everyone else, while he gets an extra sheep. Since everyone does it, the result is massive overgrazing and lots of starving sheep.
Well, okay, so it’s a parable about the awful, ineluctable consequences of not having private property in land. But the parable presupposes that you have private property in sheep, does it not?