'Elegance,' 'Symmetry,' and 'Unity': Is Scientific Truth Always Beautiful?
"Today the grandest quest of physics is to render compatible the laws of quantum physics—how particles in the subatomic world behave—with the rules that govern stars and planets. That’s because, at present, the formulas that work on one level implode into meaninglessness at the other level. This is deeply ungainly, and significant when the two worlds collide, as occurs in black holes. The quest to unify quantum physics (micro) and general relativity (macro) has spawned heroic efforts, the best-known candidate for a grand unifying concept presently being string theory. String theory proposes that subatomic particles are not particles at all but closed or open vibrating strings, so tiny, a hundred billion billion times shorter than an atomic nucleus’s diameter, that no human instrument can detect them. It’s the “music of the spheres”—think vibrating harp strings—made literal.
A concept related to string theory is “supersymmetry.” Physicists have shown that at extremely high energy levels, similar to those that existed a micro-blink after the big bang, the strength of the electromagnetic force, and strong and weak nuclear forces (which work only on subatomic levels), come tantalizingly close to converging. Physicists have conceived of scenarios in which the three come together precisely, an immensely intellectually and aesthetically pleasing accomplishment. But those scenarios imply the existence of as-yet-undiscovered “partners” for existing particles: The electron would be joined by a “selectron,” quarks by “squarks,” and so on. There was great hope that the $8-billion Large Hadron Collider would provide indirect evidence for these theories, but so far it hasn’t. (…)
[Marcelo Gleiser]: “We look out in the world and we see a very complicated pattern of stuff, and the notion of symmetry is an important way to make sense of the mess. The sun and moon are not perfect spheres, but that kind of approximation works incredibly well to simulate the behavior of these bodies.”
But the idea that what’s beautiful is true and that “symmetry rules,” as Gleiser puts it, “has been catapulted to an almost religious notion in the sciences,” he says. In his own book A Tear at the Edge of Creation (Free Press), Gleiser made a case for the beauty inherent in asymmetry—in the fact that neutrinos, the most common particles in the universe, spin only in one direction, for example, or that amino acids can be produced in laboratories in “left-handed” or “right-handed” forms, but only the “left-handed” form appears in nature. These are nature’s equivalent of Marilyn Monroe’s mole, attractive because of their lopsidedness, and Orrell also makes use of those examples.
But Weinberg, the Nobel-winning physicist at the University of Texas at Austin, counters: “Betting on beauty works remarkably well.” The Large Hadron Collider’s failure to produce evidence of supersymmetry is “disappointing,” he concedes, but he notes that plenty of elegant theories have waited years, even decades, for confirmation. Copernicus’s theory of a Sun-centered universe was developed entirely without experiment—he relied on Ptolemy’s data—and it was eventually embraced precisely because his description of planetary motion was simply more economical and elegant than those of his predecessors; it turned out to be true.
Closer to home, Weinberg says his own work on the weak nuclear force and electromagnetism had its roots in remarkably elegant, purely abstract theories of researchers who came before him, theories that, at first, seemed to be disproved by evidence but were too elegant to stop thinking about. (…)
To Orrell, it’s not just that many scientists are too enamored of beauty; it’s that their notion of beauty is ossified. It is “kind of clichéd,” Orrell says. “I find things like perfect symmetry uninspiring.” (In fairness, the Harvard theoretical physicist Lisa Randall has used the early unbalanced sculptures of Richard Serra as an example of how the asymmetrical can be as fascinating as the symmetrical, in art as in physics. She finds this yin-yang tension perfectly compatible with modern theorizing.)
Orrell also thinks it is more useful to study the behavior of complex systems rather than their constituent elements. (…)
Outside of physics, Orrell reframes complaints about “perfect-model syndrome” in aesthetic terms. Classical economists, for instance, treat humans as symmetrical in terms of what motivates decision-making. In contrast, behavioral economists are introducing asymmetry into that field by replacing Homo economicus with a quirkier, more idiosyncratic and human figure—an aesthetic revision, if you like. (…)
The broader issue, though, is whether science’s search for beautiful, enlightening patterns has reached a point of diminishing returns. If science hasn’t yet hit that point, might it be approaching it? The search for symmetry in nature has had so many successes, observes Stephon Alexander, a Dartmouth physicist, that “there is a danger of forgetting that nature is the one that decides where that game ends.”
The Asymmetry of Life
Image courtesy of Ben Lansky
"Look into a mirror and you’ll simultaneously see the familiar and the alien: an image of you, but with left and right reversed.
Left-right inequality has significance far beyond that of mirror images, touching on the heart of existence itself. From subatomic physics to life, nature prefers asymmetry to symmetry. There are no equal liberties when neutrinos and proteins are concerned. In the case of neutrinos, particles that spill out of the sun’s nuclear furnace and pass through you by the trillions every second, only leftward-spinning ones exist. Why? No one really knows.
Proteins are long chains of amino acids that can be either left- or right-handed. Here, handedness has to do with how these molecules interact with polarized light, rotating it either to the left or to the right. When synthesized in the lab, amino acids come out fifty-fifty. In living beings, however, all proteins are made of left-handed amino acids. And all sugars in RNA and DNA are right-handed. Life is fundamentally asymmetric.
Is the handedness of life, its chirality (think chiromancer, which means “palm reader”), linked to its origins some 3.5 billion years ago, or did it develop after life was well on its way? If one traces life’s origins from its earliest stages, it’s hard to see how life began without molecular building blocks that were “chirally pure,” consisting solely of left- or right-handed molecules. Indeed, many models show how chirally pure amino acids may link to form precursors of the first protein-like chains. But what could have selected left-handed over right-handed amino acids?
My group’s research suggests that early Earth’s violent environmental upheavals caused many episodes of chiral flip-flopping. The observed left-handedness of terrestrial amino acids is probably a local fluke. Elsewhere in the universe, perhaps even on other planets and moons of our solar system, amino acids may be right-handed. But only sampling such material from many different planetary platforms will determine whether, on balance, biology is lefthanded, right-handed, or ambidextrous.”
— Marcelo Gleiser, The Asymmetry of Life, § SEEDMAGAZINE, Sep 7, 2010.
"One of the deepest consequences of symmetries of any kind is their relationship with conservation laws. Every symmetry in a physical system, be it balls rolling down planes, cars moving on roads, planets orbiting the Sun, a photon hitting an electron, or the expanding Universe, is related to a conserved quantity, a quantity that remains unchanged in the course of time. In particular, external (spatial and temporal) symmetries are related to the conservation of momentum and energy, respectively: the total energy and momentum of a system that is temporally and spatially symmetric remains unchanged.
The elementary particles of matter live in a reality very different from ours. The signature property of their world is change: particles can morph into one another, changing their identities. […] One of the greatest triumphs of twentieth-century particle physics was the discovery of the rules dictating the many metamorphoses of matter particles and the symmetry principles behind them. One of its greatest surprises was the realization that some of the symmetries are violated and that these violations have very deep consequences. (…) p.27
Even though matter and antimatter appear in equal footing on the equations describing relativistic particles, antimatter occurs only rarely. […] Somehow, during its infancy, the cosmos selected matter over antimatter. This imperfection is the single most important factor dictating our existence. (…)
Back to the early cosmos: had there been an equal quantity of antimatter particles around, they would have annihilated the corresponding particles of matter and all that would be left would be lots of gamma-ray radiation and some leftover protons and antiprotons in equal amounts. Definitely not our Universe. The tiny initial excess of matter particles is enough to explain the overwhelming excess of matter over antimatter in today’s Universe. The existence of mattter, the stuff we and everything else are made of, depends on a primordial imperfection, the matter-antimatter asymmetry. (…) p.29.
We have seen how the weak interactions violate a series of internal symmetries: charge conjugation, parity, and even the combination of the two. The consequences of these violations are deeply related to our existence: they set the arrow of time at the microscopic level, providing a viable mechanism to generate the excess of matter over antimatter. […] The message from modern particle physics and cosmology is clear: we are the products of imperfections in Nature. (…)
It is not symmetry and perfection that should be our guiding principle, as it has been for millennia. We don’t have to look for the mind of God in Nature and try to express it through our equations. The science we create is just that, our creation. Wonderful as it is, it is always limited, it is always constrained by what we know of the world. […] The notion that there is a well-defined hypermathematical structure that determines all there is in the cosmos is a Platonic delusion with no relationship to physical reality. (…) p. 35.
The critics of this idea miss the fact that a meaningless cosmos that produced humans (and possibly other intelligences) will never be meaningless to them (or to the other intelligences). To exist in a purposeless Universe is even more meaningful than to exist as the result of some kind of mysterious cosmic plan. Why? Because it elevates the emergence of life and mind to a rare event, as opposed to a ubiquitous and premeditated one. For millennia, we believed that God (or gods) protected us from extinction, that we were chosen to be here and thus safe from ultimate destruction. […]
When science proposes that the cosmos has a sense of purpose where in life is a premeditated outcome of natural events, a similar safety blanket mechanism is at play: if life fails here, it will succeed elsewhere. We don’t really need to preserve it. To the contrary, I will argue that unless we accept our fragility and cosmic loneliness, we will never act to protect what we have. (…)
The laws of physics and the laws of chemistry as presently understood have nothing to say about the emergence of life. As Paul Davies remarked in Cosmic Jackpot, notions of a life principle suffer from being teleologic, explaining life as the end goal, a purposeful cosmic strategy. The human mind, of course, would be the crown jewel of such creative drive. Once again we are “chosen” ones, a dangerous proposal. […] Arguments shifting the “mind of God” to the “mind of the cosmos” perpetuate our obsession with the notion of Oneness. Our existence need not be planned to be meaningful.” (…) p.49.
Unified theories, life principles, and self-aware universes are all expressions of our need to find a connection between who we are and the world we live in. I do not question the extreme importance of understanding the connection between man and the cosmos. But I do question that it has to derive from unifying principles. (…) p.50.
My point is that there is no Final Truth to be discovered, no grand plan behind creation. Science advances as new theories engulf or displace old ones. The growth is largely incremental, punctuated by unexpected, worldview-shattering discoveries about the workings of Nature. […]
Once we understand that science is the creation of human minds and not the pursuit of some divine plan (even if metaphorically) we shift the focus of our search for knowledge from the metaphysical to the concrete. (…) p.51.
For a clever fish, water is “just right“ for it to swim in. Had it been too cold, it would freeze; too hot, it would boil. Surely the water temperature had to be just right for the fish to exist. “I’m very important. My existence cannot be an accident,” the proud fish would conclude. Well, he is not very important. He is just a clever fish. The ocean temperature is not being controlled with the purpose of making it possible for it to exist. Quite the opposite: the fish is fragile. A sudden or gradual temperature swing would kill it, as any trout fisherman knows. We so crave for meaningful connections that we see them even when they are not there.
We are soulful creatures in a harsh cosmos. This, to me, is the essence of the human predicament. The gravest mistake we can make is to think that the cosmos has plans for us, that we are somehow special from a cosmic perspective. (…) p.52
We are witnessing the greatest mass extinction since the demise of the dinosaurs 65 million years ago. The difference is that for the first time in history, humans, and not physical causes, are the perpetrators. […] Life recovered from the previous five mass extinctions because the physical causes eventually ceased to act. Unless we understand what is happening and start acting toghether as a species we may end up carving the path toward our own destruction. (…)” p.56
— Marcelo Gleiser is the Appleton Professor of Natural Philosophy at Dartmouth College, A Tear at the Edge of Creation, Free Press, 2010.
☞ Symmetry in Physics - Bibliography - PhilPapers
☞ The Concept of Laws. The special status of the laws of mathematics and physics, Lapidarium notes
☞ Universe tag on Lapidarium notes