Given complex vertebrates what is the likelihood of abstract intelligence
Let's start with a biological system that already has vertebrates. This gives us a very powerful starting point for evolution to work from. We have had complex vertebrates for at least 250 millions or so. If you look at the evolutionary history it is pretty amazing that we are the only intelligent species to arise. This would seem to have implications for the probability of intelligent life forming. The raw material for intelligence has been available for a very, very long time yet we only recently developed abstract thought. Put another way, you can look at the evolutionary record as a sort of sample space or a set of trials. We see no evidence for abstract thought until us. The fact that we have only recently formed intelligent life is additional evidence for how unlikely it is to happen.