> I've never understood how biologists could argue non-selfish evolution couldn't be a thing. If you look at groups of organisms as systems, and you pit the sys

> I've never understood how biologists could argue non-selfish evolution couldn't be a thing. If you look at groups of organisms as systems, and you pit the systems against each other, surely eventually the system that evolved to be superior would win in the end, regardless of whether that means any subspecies in that group of organisms would evolve to not reproduce? Of course, all other things equal, when you pit groups against each other then group selection will occur. But the problem is that a huge body of science, both theoretical (game theory) and observational, argues that things are not equal: At the same time as the groups are competing, there is in-group competition. There has to be, because the groups consist of organisms that are being selected for, unless someone can propose a mechanism that would suppress that. What this means is that group selection is unstable. A group behavior might be selected for, but individuals in the successful group will still be selected for "selfishly" - normally - breaking the pattern. If selection operates on the gene level - and almost all biologists believe it does - then it is inherently going to act on a scale much smaller than that of groups, and in an inevitable manner. And that is going to destabilize any group selection. For these reasons it was thought that altruism couldn't be easily explained through evolution. That's why kin selection, reciprocal alruism, and a few other theories are so revolutionary - they show how useful group behaviors arise from selection at the gene level. > Is it not just a question of whether evolution could produce specialized one-offs that don't reproduce but do serve a purpose? That does occur in the "eusocial" animals, such as ants and bees. But it is generally believed that happens due to how genes are passed on in those insects (different than we are used to among mammals), and they are a large exception. In practically every species we are aware of, group-level selection does not occur. Hence any evidence, as in this article, is very interesting.