>We can find the maximum head-size that fits through a vaginal canal, or the maximum metabolic rate a human body could support, and try to determine if these fa

>We can find the maximum head-size that fits through a vaginal canal, or the maximum metabolic rate a human body could support, and try to determine if these factors imposed any limitations on intelligence during human evolution. Head sizes have been larger in human history and some human relatives with larger brains died out. Energy consumption on the other hand is a limiting factor for every computational device and energy efficiency tends to be a key category where Nature still wins. In particular, the liver and enzymes of various plants and microbes can perform chemical reactions in water at ambient temperature that we can't do at all; resilin is still a more efficient elastic material than any synthetic elastomer; artificial piezoelectric muscles have less than a tenth the energy efficiency of real ones, and of course lots of animals are able to run around in polar and desert regions we still can't traverse because of the fuel and material costs etc. One particularly revealing example is to calculate the ratio between: * the performance per watt of the most efficient supercomputer (7 GFlops/watt) vs the human brain (38 petaflops / 20 watts = 1.9 petaflops per watt) * the performance per watt of the human brain vs the Landauer limit at body temperature (don't remember)