[0xdde]

What principle of basic game theory would that be? You also need to justify the incredibly strong assumption that "any sacrifice" has "highly negative effects" on the individual player. An immediate counterexample would be beef consumption. For many people, reducing their intake would have positive effects on their health.

[silverquiet]

I'll raise my hand here. The anxiety of seeing the Earth on an inevitable path towards ruin became overwhelming for me a few years ago. In order to deal with it, I have made some sacrifices. I live with roommates in order to reduce my energy use. I eat in ways that are more sustainable. I do not fly on planes. I drive a very efficient car and would walk/bike more, but I have a bad hip and am already fairly limited by it. The car still causes me some guilt. I don't believe that my individual sacrifices make any difference at all, and perhaps are just my own way of engaging in denial.