How so? It seems to me a good many folks jump from one to the other while interpreting and exlaining the evidence. Don't they need to be "set straight?"
FC: How so? It seems to me a good many folks jump from one to the other while interpreting and exlaining the evidence.
It sure looks like a continuum. You've got dogs and cats (can't breed), horses and donkeys (can, but infertile offspring), lions and tigers (zoo keepers can force them to, don't know if the offspring are fertile), ring species (A breeds w/ B, B w/ C, C w/ D, but A and D can't), domestic dogs (chihuahuas and Great Danes physically can't, imagine the pups would be fertile if we did it artificially)
Where's micro? where's macro?
I'm reminded of Archimedes' Axiom: given any quantity e, no matter how small (but bigger than zero), and given another quantity M, no matter how large (but finite), there is a whole number K such that K times e is bigger than M. (Seems obvious, but there are number systems in which it is false, the so-called non-Archimedean fields)