The little things

Tungsten diboride (WB₂) is extraordinarily stiff and resistant to deformation and scientists have long suspected it could be a superhard material, meaning it scores at least 40 gigapascal (GPa) on a hardness test. This is important because diamond, the hardest natural material on Earth, scores 70-100 GPa but because it is so expensive, industries often turn to cubic boron nitride (45-60 GPa) as a substitute in tools to cut metals and ceramics. Another superhard material in the repertoire could be a good thing. The problem is WB₂ is also brittle: like glass, it is hard to scratch but easy to shatter. This is because its atoms are so strongly bonded to each other that the bulk crystal would sooner fracture than a few bonds yield. So Southern University of Science and Technology, Shenzhen, researchers doped WB₂ with rhenium, a rare metal that has one more electron than the tungsten atom. This electron changes the way atoms pack together inside a crystal, coaxing the tungsten and rhenium atoms into leaving behind vacancies in the grid of atoms in a specific, repeating pattern. These vacancies were arranged in ordered pairs along particular planes inside the crystal that allowed the atoms to ‘glide’ past each other when they were stressed, effectively allowing the crystal to bend a little to absorb pressure rather than bottle it up and break catastrophically later. The team measured this version of WB₂ to have a hardness of 40 GPa and for added measure the rhenium also increased the temperature at which the crystal rusted by 700° C.

By removing a few atoms the scientists effectively made the material a lot less brittle and better able to withstand heat. Little things like this are a reminder that what we know to be true at one scale or context does not necessarily hold true at all scales and contexts. And this is as true as an allegory as it is a scientific fact. Social media platforms as well as TV news in India are rife these days with unfounded speculation and unsubstantiated claims, many of which extrapolate from small pools of information without a modicum of good faith or introspection as to whether what we already know may not suffice to describe or explain the things happening around us. I am for people using AI models in some enterprises but, as with cryptocurrencies, most of their more visible users have pressed them in the service of newfangled Ponzi schemes and scams and, curiously, to mouth off about ‘revitalising’ physics research, so to speak, without stopping to think about what they do not know and, perhaps more importantly, the possibility that, to combine two famous lines associated with Richard Feynman and Freeman Dyson, there is always more room in all directions and more — as Philip Warren Anderson wrote in 1972 — is different. The BS is often manifest as accounts on X.com purporting to have ‘solved’ quantum gravity or resolving open questions in particle physics, which may be a scam as well insofar as they come off as efforts to privatise such research and have it enter the hype cycles of venture capitalists.

On a less dismaying note, new forms of organisation do not emerge because the fundamental laws of nature change but because, as with superhard tungsten diboride, groups of things can act together in ways that their individual members do not or because they have been exposed to new environments we have yet to encounter them in. There are other possibilities, too. For instance, these days I am regularly surprised by what scientists are finding out about things animals are capable of. Jane Goodall found chimpanzees use tools, and now it seems so can some fish, birds, and cows. I also understand that there are forms of emergence to be found in the study of societies, religions, history, and art. While it is obvious that the source of surprise always seems to be us not knowing enough while going in thinking we do, the prescient words of Anderson from that 1972 essay come to mind (let it be known that I will never tire of quoting him at length):

The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe. In fact, the more the elementary particle physicists tell us about the nature of the fundamental laws the less relevance they seem to have to the very real problems of the rest of science, much less to those of society.

The constructionist hypothesis breaks down when confronted with the twin difficulties of scale and complexity. The behavior of large and complex aggregates of elementary particles, it turns out, is not to be understood in terms of a simple extrapolation of the properties of a few particles. Instead, at each level of complexity entirely new properties appear, and the understanding of the new behaviors requires research which I think is as fundamental in its nature as any other. That is, it seems to me that one may array the sciences roughly linearly in a hierarchy, according to the idea: The elementary entities of science X obey the laws of science Y.

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The arrogance of the particle physicist and his intensive research may be behind us (the discoverer of the positron said “the rest is chemistry”), but we have yet to recover from that of some molecular biologists, who seem determined to try to reduce everything about the human organism to “only” chemistry, from the common cold and all mental disease to the religious instinct. Surely there are more levels of organization between human ethology and DNA than there are between DNA and quantum electrodynamics, and each level can require a whole new conceptual structure.

In closing, I offer two examples from economics of what I hope to have said. Marx said that quantitative differences become qualitative ones, but a dialogue in Paris in the 1920’s sums it up even more clearly:

FITZGERALD: The rich are different from us.

HEMINGWAY: Yes, they have more money.