Here’s another of those Dawkins questions.
Stuart Kauffman’s thought experiment: If evolution could be re-run 1000 times, would certain patterns predictably recur? Humanoids?
Only I already answered it a few weeks ago! I know that Dawkins is more sympathetic to the idea of evolutionary convergence than I am, but I don’t think you’d get recurrence of humanoids. If we could reset everything to the precise state the world was in during the Cambrian, half a billion years ago, I think it would be safe to say we’d get a planet full of molluscs and arthropods, but that’s about all we could say — tetrapods are not inevitable. If we could rewind to a few billion years ago, before the evolution of eukaryotes, we could talk about a planet of algae and bacteria, but other derived forms would be so contingent on chance that no prediction is possible.
The best examples of actually doing this experiment come from the Lenski lab and their work on bacteria, where generations could be frozen and restarted at will, and the answer is…no, it isn’t inevitable that a lineage will emerge that carries even an expected optimal simple biochemical pathway.