Roll Over Voltaire
Three hundred years ago Gottfried Leibniz said we live in the best of all possible worlds but today Princeton’s world reknown theorist William Bialek explains that it is more perfect than we imagined. This video is long and it sometimes dwells on Bialek rather than the slide he is talking to, but those drawbacks are minor compared to what you will learn. If you want to hear an intelligent, thoughtful scientist scratch the surface of creation’s wonders and reflect on what it all means, then this video is for you.
Bialek, for instance, discusses compound eyes of insects such as the fly. These compound eyes have a large number of small lenses packed into an array. A large number of small lenses gives high resolution, just as does a digital camera with a large number of pixels.
But when the lens becomes too small its optics become distorted due to diffraction. So in determining the best lens size there is a tradeoff between resolution and diffraction. In the optimum solution the lens size is roughly proportional to the square root of the radius of the head. An indeed, Bialek shows an old paper surveying the compound eye designs in more than two dozen different insects. That paper shows that for the different size insects, the lens size is proportional, as predicted, to the square root of the head size.
This is one of Bialek’s half a dozen or so examples showing the optimization of biological designs and, as Bialek assures the audience, there are many, many more. Here is how one science writer explained it:
Yet for all these apparent flaws, the basic building blocks of human eyesight turn out to be practically perfect. Scientists have learned that the fundamental units of vision, the photoreceptor cells that carpet the retinal tissue of the eye and respond to light, are not just good or great or phabulous at their job. They are not merely exceptionally impressive by the standards of biology, with whatever slop and wiggle room the animate category implies. Photoreceptors operate at the outermost boundary allowed by the laws of physics, which means they are as good as they can be, period. Each one is designed to detect and respond to single photons of light — the smallest possible packages in which light comes wrapped.
“Light is quantized, and you can’t count half a photon,” said William Bialek, a professor of physics and integrative genomics at Princeton University. “This is as far as it goes.” …
Photoreceptors exemplify the principle of optimization, an idea, gaining ever wider traction among researchers, that certain key features of the natural world have been honed by evolution to the highest possible peaks of performance, the legal limits of what Newton, Maxwell, Pauli, Planck et Albert will allow. Scientists have identified and mathematically anatomized an array of cases where optimization has left its fastidious mark, among them the superb efficiency with which bacterial cells will close in on a food source; the precision response in a fruit fly embryo to contouring molecules that help distinguish tail from head; and the way a shark can find its prey by measuring micro-fluxes of electricity in the water a tremulous millionth of a volt strong — which, as Douglas Fields observed in Scientific American, is like detecting an electrical field generated by a standard AA battery “with one pole dipped in the Long Island Sound and the other pole in waters of Jacksonville, Fla.” In each instance, biophysicists have calculated, the system couldn’t get faster, more sensitive or more efficient without first relocating to an alternate universe with alternate physical constants.
But there is much more to Bialek’s talk than examples of nature’s optimal designs. In a thoughtful segment Bialek discusses his philosophy of science. At the [16:30] mark he asks “That was fun, but what does it mean?” The answer, he begins, is that nature’s many examples of optimization help to highlight the difference between two ways of doing and thinking about science.
Bialek describes a cartoon in which a family is driving the car over a bridge with a posted weight limit. The son asks the father how they know what is the weight limit. The father responds that they wait until a sufficiently heavy truck destroys the bridge, they then weigh the remains of the truck, rebuild the bridge exactly as it was, and post the sign.
Bialek uses this funny cartoon as a metaphor for evolutionary theory’s reliance on contingency. This trial-and-error approach to understanding and invention is, Bialek explains, a very common view. The species are the way they are because that is the way they happened to evolve.
In fact, Bialek cogently points out, evolution’s promotion of contingency and trial-and-error is not so much out of scientific necessity. In the bridge example, we could actually model and compute the load limit, based on the design of the bridge and the types of materials used.
But given the “political context” in which many of these discussion occur, it is understandable why evolution is presented as a process of tinkering and not design. [19:30] In fact, the Yale biophysicist notes, these arguments are opposed to the idea of a “interventionist designer,” rather than the question of whether there are design principles in biology.
Bialek contrasts this approach with another view—the view that guides so many physicists—which he represents with Galileo’s famous quote that “The book of Nature is written in the language of mathematics.” Physics, Bialek points out, has been remarkably successful using this formula. It is, he notes, an “astonishing achievement” of the human mind over these four hundred past years. Bialek laments the evolutionary view that Galileo would never have said such a thing if he had known about biology.
Bialek’s point that evolution opposes the idea of a interventionist designer is crucial. For far from reflecting atheism, as so many have charged, and far from being a scientific finding as today’s positivist sentiment wants to believe, this foundation of evolutionary thought is religious.
That is not to say evolution is right or wrong, or true or false. It simply is religious. And until we understand the religion we are immersed in, we will not comprehend its influence on our thinking.
Without this religion, which is ubiquitous, evolution could certainly continue as a theory of mechanical origins. But evolutionary thought would be stripped of its core theoretic and its metaphysical certainty. The theory of evolution would then, rather than be mandated to be a fact, lie exposed to the light of science which shows it to be so improbable.
But it is precisely this distinction, this parsing of the religion from the science, that is so difficult to achieve. When I first began to study the evolutionary literature I was constantly fooled by its intertwining of metaphysics with the empirical science. The evolution literature is rife with religious claims in hiding.
But when properly distinguished and separated, one immediately can see that the conviction of evolution’s truth lies in the non scientific claims whereas the empirical evidence, alone, gives us no such confidence.
Religion drives science, and it matters.