Natural Selection (Evolution)
Pretty much took the words out of my mouth; I just didn't want to be the first one to bring up age. (not negatively, mind!) I entered college when many findings were already accepted and things were assimilated into a "newer" theory of evolution. I think this might be a difference for dhw and myself as well... we'll see...-My brain is shrinking, his is also (at age 71-72):>))