Evolution, either genetic or cultural, doesn't have infinite search capacity. We can evaluate which of our adaptations actually are promoting or enforcing symmetric cooperation in the IPD, and which are still climbing that hill, or are harmless extraneous adaptations generated by the search but not yet optimised away by selection pressures.
But we are our adaptations. Are you claiming morality should be defined by evolutionary fitness? (So we should tile the universe by our DNA?) How is that better than other external sources of morality? We already have a morality, it doesn't matter (for the purpose of being moral) where it came from, be it God or evolution.
Also, saying the morality comes from solving PD doesn't help, since PD already assumes the agents have utility functions. Game theory is only directly relevant to rationality, not morality. If you and I are playing a non-zero sum game then we better cooperate for our own good. But the fact that my utility function already includes your well-being is completely independent.
I agree that evolutionary thinking can be helpful to figure out what our morality is (since moral intuition is low bandwidth and noisy), but I'm against imaginary extrapolations of evolution.
The 'Irrationality Game' posts in discussion came before my time here, but I had a very good time reading the bits written in the comments section. I also had a number of thoughts I would've liked to post and get feedback on, but I knew that being buried in such old threads not much would come of it. So I asked around and feedback from people has suggested that they would be open to a reboot!
I hereby again quote the original rules:
I would suggest placing *related* propositions in the same comment, but wildly different ones might deserve separate comments for keeping threads separate.
Make sure you put "Irrationality Game" as the first two words of a post containing a proposition to be voted upon in the game's format.
Here we go!
EDIT: It was pointed out in the meta-thread below that this could be done with polls rather than karma so as to discourage playing-to-win and getting around the hiding of downvoted comments. If anyone resurrects this game in the future, please do so under that system If you wish to test a poll format in this thread feel free to do so, but continue voting as normal for those that are not in poll format.