In other words, my point is that if the signaling is about your future property, at the moment when you have to perform the promised behavior, there is no need for any kind of persistence, thus according to your definition precommitment is unnecessary. Likewise, signaling doesn't need to consist in you presenting any kind of argument, it may already be known that you (will be) a cooperator.
For example, the agent in question may be selected from a register of cooperators, where 99% of them are known to be cooperators. And cooperators themselves might as well be human, who decided to follow this counterintuitive algorithm, and benefit from doing so when interacting with other known cooperators, without any tangible precommitment system in place, no punishment for not being cooperators. This example may be implemented through reputation system.
No such thing as future property. This isn't a factual disagreement on my part, just a quibble over terms; disregard it.
Your example isn't about signaling or precommitment, it's changing the game into multiple-shot, modifying the agent's utility function in an isolated play to take into account their reputation for future plays. Yes, it works. But doesn't help much in true one-shot (or last-play) situations.
On the other hand, the ideal platonic PD is also quite rare in reality - not as rare as Newcomb's, but still. You may remember us having an isomorphic ...
I spoke yesterday of the epistemic prisoner's dilemma, and JGWeissman wrote:
To which I said:
And lo, JGWeissman saved me a lot of writing when he replied thus:
I make one small modification. You and your creationist friend are actually not that concerned about money, being distracted by the massive meteor about to strike the earth from an unknown direction. Fortunately, Omega is promising to protect limited portions of the globe, based on your decisions (I think you've all seen enough PDs that I can leave the numbers as an excercise).
It is this then which I call the true epistemic prisoner's dilemma. If I tell you a story about two doctors, even if I tell you to put yourself in the shoes of one, and not the other, it is easy for you to take yourself outside them, see the symmetry and say "the doctors should cooperate". I hope I have now broken some of that emotional symmetry.
As Omega lead the creationist to the other room, you would (I know I certainly would) make a convulsive effort to convince him of the truth of evolution. Despite every pointless, futile argument you've ever had in an IRC room or a YouTube thread, you would struggle desperately, calling out every half-remembered fragment of Dawkins or Sagan you could muster, in hope that just before the door shut, the creationist would hold it open and say "You're right, I was wrong. You defect, I'll cooperate -- let's save the world together."
But of course, you would fail. And the door would shut, and you would grit your teeth, and curse 2000 years of screamingly bad epistemic hygiene, and weep bitterly for the people who might die in a few hours because of your counterpart's ignorance. And then -- I hope -- you would cooperate.