One might argue that the key insights for AI are embodied in the structure of nervous systems, which came into existence less than a billion years ago.8 If we take that view, then the number of relevant “experiments” available to evolution is drastically curtailed. There are some 4–6×1030 prokaryotes in the world today, but only 1019 insects, and fewer than 1010 humans (while pre-agricultural populations were orders of magnitude smaller).9 These numbers are only moderately intimidating.
