Unfortunately, disallowing notions of group selection also disallows notions of
emergent higher-level-order systems. You must allow for selection effects at all
significantly functioning layers/levels of the emergent system, to explain the emergence
of these systems adequately. For example, ant colonies (as an emerged system) live
for 15 years whereas the ants live for at most a year. Yet the colony (controlling for
colony size) behaves diffently when it is a young colony (say its first five years) compared
to when it is in its old age. (Essentially, the colony's behaviours become more
conservative (less amenable to change of tactics.))
It would be very difficult to explain this solely from the perspective of the direct benefit
to any individual ant's genes. For the benefit of ant-genes in general in the colony,
yes.
I think that it's just been too difficult to get adequate controlled studies to determine
whether a group selection effect is happening. Because the individuals tend not to
live at all if removed from their group.
I think it is still an open debate. Group selection being discredited is just Dawkins
and some like-minded people's favorite theory right now.
Group selection is now discredited as an evolutionary force.
See http://www.utm.edu/~rirwin/391LevSel.htm for some class lecture notes discussion group selection.
