“A set of near optimal mechanisms”

“A set of near optimal mechanisms” April 8, 2018


A cat. Not necessarily your friend.
Cats are remarkable creatures.    (Wikimedia Commons)


Douglas Axe studied engineering and molecular biology at the University of California at Berkeley and at the California Institute of Technology (Caltech), where he earned his doctorate.  He then did postdoctoral research at Cambridge University in England, followed by a stint as a research scientist there.


Here, in his book Undeniable: How Biology Confirms Our Intuition That Life is Designed (New York: HarperOne, 2016), Dr. Axe quotes from the Princeton physicist William Bialek, who, he says, “heads a research team that measures how well various biological functions are performed relative to the lofty standard of physical perfection”:


Strikingly, when we do this (and there are not so many cases where it has been done!), the performance of biological systems often approaches some limits set by basic physical principles.  While it is popular to view biological mechanisms as an historical record of evolutionary and developmental compromises, these observations on functional performance point toward a very different view of life as having selected a set of near optimal mechanisms for its most crucial tasks. . . . The idea of performance near the physical limits crosses many levels of biological organization, from single molecules to cells to perception and learning in the brain, and I have tried to contribute to this whole range of problems.  (cited on 269)


Dr. Axe comments on Professor Bialek’s observation:


In other words, in design situations where human engineers would want to push the limits of physical possibility if they could, we often find that biological systems operate at or near those limits.

There’s more subtlety to this claim than I can unpack in a few words, and some may be inclined to dismiss it for that reason.  To fully grasp the point, you have to look quite deeply into actual design constraints and objectives.  For example, gazelle legs don’t propel gazelles to speeds remotely approaching the speed of light (the absolute physical speed limit), but then neither would human engineers set out to make an all-terrain vehicle that moves anywhere near that speed.  On the other hand, the eyes of cats do approach the physical limit of single-photon sensitivity, and the antennae of certain male moths do achieve single-molecule sensitivity to sex pheromones, and certain enzymes do approach the physical limit of proficiency — processing their reactant moelcules as fast as diffusion can deliver them.  To anyone with an appreciation of design challenges, the long list of believe-it-or-not facts like these coming from biology is truly astounding.  (270)



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