If that's the difference between game theory and instrumentalism, I think there's a tension in some of what you've said beforehand. Is game theory value-neutral or not? Does it prescribe outcomes by showing how behaviour is directed towards success? Earlier, you made it sound as if societies go their separate ways, depending on their ethos, and game theory doesn’t evaluate which society is best.

But you’ve also said that plus-sum outcomes are better or more fundamental in nature, and now you’re assuming that game theory has some ideal of success.

In any case, instrumentalism likewise has such a standard since it’s built into the idea of having a goal, purpose, or desire. If you want to be an astronaut, you have various options and some will be better than others, which is to say they’re more efficient at achieving the goal. Instrumentalists evaluate the means relative to the end, but not so much the ultimate desires.

Game theory looks to me like instrumentalism applied to the goal of maintaining a healthy society. So game theorists try to map out which social behaviours are most efficient in achieving that goal, by looking at the relationships between strategies and outcomes.

I don’t see why instrumentalism or game theory should entail, though, a cynical or reductionistic take on the non-mathematical explanations of what’s going on in society. There are a lot of nuances that math or any lofty abstraction misses. So that’s a philosophical stance on top of game theory.

Anyway, I thank you for your very thought-provoking comments, and I’m always happy to read them. I hope I gave you something to think about too.