Lightman's Universe

A little anarchy goes a long way.

Posted Dec 16, 2015

J. Krueger
Asymmetric deer
Source: J. Krueger

A penny for your pensées. ~Fermat to Pascal

Multiverse, shmultiverse

Alan Lightman, an eminent physicist at MIT, recently (2013) published a wise and humane book called The accidental universe. Lightman is an atheist and he is not seduced by quantum physics, string theory, or Deepak Chopra to think that god is more likely to exist than not. The most profound point Lightman makes is found on the last page (p. 22) of the first essay, which is also called “The accidental universe.” Lightman asserts that “to explain what we see in the world and our mental deductions, we must believe in what we cannot prove.” This is no revelation to any theory-minded scientist. At the base of any theory lie assumptions so deep that they are beyond the reach of empirical fishing. They are useful and necessary, however, in that they give coherence to that which can be seen and allow us to generate testable predictions. We must believe, for example, that there is dark matter and dark energy in order to make sense of the behavior of galaxies.

Much as I agree with Lightman’s foundational assertion, I think his crowning example is a poor choice. He writes that “we must believe in the existence of many other universes” (p. 21). Lightman derives this commandment from his earlier conclusion that “we must accept that basic properties of our universe are accidental and uncalculable” (p. 21). He does not say explicitly that the accidental nature of this universe entails the existence of others, but this is what I take him to mean. Well, it does not follow.

To illustrate the ‘it-does-not-follow’ argument, I went downstairs to see one of my friends in the IT department. I showed him a quarter and I asked him if the coin was fair. After handling and inspecting it, he said yes. Then I flipped the coin and he called it (incorrectly, as it turned out). I asked him if the process of coin-flipping was fair. He said yes. Was it random? Yes. Would it still be random if it was the only coin flip ever performed? Yes. By analogy we may assume with Lightman that the specific settings of our universe (e.g., the number and strength of the basic forces, the number of dimensions) emerge from irreducible randomness. Such randomness could have produced a very large number of universes, and hence a multiverse. If so, our particular universe would be the result of one of this very large number of cosmic coin tosses. But then, perhaps there was just one toss, and here we are, anthropically principled. To think that randomness implies the existence of many random events is an instance of a reverse-inference fallacy. If there are many events (coin tosses or universes), we can test whether a random model fits. If there is only one event, we cannot do this, and the belief that this one event was generated by a random process is one of those foundational ideas that “we must believe” without proof. In short, Lightman tried to prove his claim (“we must believe”) by violating it (leaning illogically on the idea that we also must believe in the multiverse).

Nevertheless, Lightman’s conclusion that sometimes we must believe that which we cannot prove is a profound insight. What Lightman also knows, but many of us often forget, is that “we-must-believe” is the choice of last resort. We can choose unprovable belief when [a] all else fails, and [b] this belief in useful in the two respects noted above.  

There are many concepts in psychology that fascinate us in part because of their unsettled standing as [i] factual things, [ii] Lightman things in whose existence we must believe without proof, and [iii] as-if things or metaphors. How, in your estimation, should we think about the mind, the self, consciousness, or the will?

Sons of symmetry

In another essay of his book, Lightman explores “The symmetrical universe,” and loses his nerve. He starts out by noting the tremendous evidence for symmetry all around us. From the roundness of Saturn to the pentagon of the beehive, all the way down to the symmetry-giving power of the Higgs particle. We are tuned to this symmetry – so Lightman – so that we may delight in its beauty. Some of these symmetries can be shown to be necessary so long as we – reasonably – assume that nature will assume whatever pattern consumes the least energy. The beehive makes this point nicely. To build hives of pentagons, bees do less work than they would with any other structures and there is no wasted space. Living things evolve along Darwinian lines, in which asymmetry means a loss of fitness. To use a crude example, if we were not at least roughly symmetrical, we could easily be knocked over by enemies or predators. In mate selection, we value symmetry because we don’t want a partner or offspring who are easily knocked over by enemies or predators. Asymmetry-bestowing genes do a poor job replicating themselves and hence we see a lot of symmetry.

When a simple and elegant hypothesis explains a lot but also leaves a lot unexplained, we need a meta-hypothesis to explain the difference. Lightman knows – but seems to underestimate – the presence of asymmetry. Planets and their orbits are not perfectly round; they are elliptoid. Plants, animals, and landscapes show plenty of asymmetry. Our hearts are on the left (for most of us) and language mostly sits in the left half of the brain. Few of us are ambidextrous. Many natural processes are chaotic rather than linear (or even random). Great Britain is not symmetrical and neither is Aunt Millie. Asymmetry is everywhere.

Lightman ties what symmetry he sees in nature to our aesthetic sense, but then does the same for asymmetry. Symmetry is pleasing, and simple math is a striking example. But then, chaos math is also pleasing. Lightman suggests that symmetry scores an aesthetic point because it implies predictability. “We find satisfaction in the repetition of the seasons and the reliability of friendships” (p. 79) he writes. Why is predictability good (and beautiful)? Because it enhances our fitness for life. If we can predict when to plant the next crop and which friend to call on to help with the harvest, we do better than if we were guessing. Not surprisingly, we like that.

But Lightman also says “we crave order in this strange universe” (p. 78), which concedes that the universe is not a terribly symmetric place; we just want it to be. And yet, “a slight bit of asymmetry is desirable and found to achieve a higher aesthetic satisfaction” (p. 80). “Perfect order in art is uninteresting [and] delight lies somewhere between boredom and confusion” (p. 81). Yes indeed, but notice that all hope for having a positive theory of aesthetics is lost. We have rejected two clear and simple hypotheses, according to which we love either symmetry or asymmetry. To say that true beauty lies somewhere in between is like saying that Aunt Millie neither lives on the East Coast nor on the West Coast. Now go and look for her.

Lightman, A. (2013). The accidental universe. New York, NY: Vintage.

German pun fun: Wie nennt man einen lebensmüden Astronom? - "Weltallergiker"