The Logical Necessity of Group Selection
There has been a long-standing debate about the notion of group selection, the idea that populations of organisms can be selected for en masse over competing populations. The Darwinian “purists” claim that natural selection (NS) only acts at the level of individuals. But if that’s true, then how can multicellular organisms be subject to NS? After all what are multicellular organisms if not a group of single cell organisms?
Part of the reason it is hard to see this basic truth is that we don’t accept that there is a continuum of behaviors between groups of agents which ranges from highly competitive on one end to highly cooperation on the other. When agents cooperate enough, we recognize a new level of agency (e.g. metazoa). But one of the thrusts of this blog is to look at group dynamics not as an all or none proposition. By admitting to this continuum, it becomes clearer how a loose ecology of independent agents, taken together with all of their cooperative dynamics can be seen as an agent which can be subject to selective pressure in the presence of other such “loose group agents.” To deny group selection is to deny NS entirely.