The gap between language and quantum mechanics

Physics World has a fantastic article about the problem with using a language invented, in Terry Pratchett's words, "to tell other monkeys where the ripe fruit is", to describe the peculiar but very much real possibilities created by the rules of quantum mechanics. Excerpt:

… despite the burgeoning growth of quantum technology, one thing that hasn’t changed is the cumbersome and counterintuitive language we use to talk about all things quantum. While the reality of entanglement and superposition is beyond all reasonable doubt, it is as maddening as ever to describe them in words. Quantum phenomena are strange, but that does not mean we should be satisfied with strange language to describe them.

From the very early days of quantum mechanics, Albert Einstein, Niels Bohr, Werner Heisenberg and others strove to understand this new-fangled non-classical physics of quantum 1.0. Their struggle concerned a gap between how we talk about phenomena and how we encounter them in the laboratory. That gap was created by the imperfect metaphorical language still largely used to characterize non-classical phenomena.

The authors have written that the terms that writers, journalists, and scientists reach for when describing quantum phenomena to people who don't have the mathematical awareness (for want of a better description) are probably adding to the confusion instead of clarifying quantum mechanics, and diminishing its realness. 'Superposition' is a good example: it's a word that captures a particular phenomenon, but when you try to spell it out, in toto with no exceptions, to someone who doesn't understand the math of it, you use some metaphors and approximations that either create an incomplete picture or an obscured one. And both add to quantum physics's mystery and spookiness, which are counterproductive.

This has been a familiar challenge in my experience covering high-energy physics as well, were the protagonists are often particles and forces that are best described using mathematical grammar (amplitudes, matrices, groups, etc.) rather than the language that facilitates everyday life. This is why I think the molasses metaphor (and minor variations of it) may well have been the most used of its kind in 2012, when the Higgs boson, and its corresponding energy field, dominated physics news: in the New York Times's words, "What is the Higgs field? … It has been described as a kind of cosmic molasses, dragging on particles as they move through it". In an instructive 2013 paper, Stewart Alsop and Steven Beale wrote (emphasis in the original) about the problems with such metaphors:

At some point, of course, all analogical thinking breaks down—the Higgs phenomena is not a crowd or molasses. Perhaps a weakness with these analogies is their reliance on a 'medium' as the object node mapped to the Higgs field. This is probably unavoidable, but it results in a number of points of potential confusion. The concept of a medium is generally understood to be a volume filled with a physical substance that can be manipulated and controlled. This is not the case in the standard model of the Higgs field, which is understood to be uniform and constant. The familiar conception of a medium is insufficient to fully understand the Higgs field in this respect. A medium can be entered and exited because it is localized, it can be concentrated in one location and minimized in another, and it is composed of matter and has its own mass and energy. Mapping these attributes onto the Higgs field leads to a line of reasoning reminiscent of 19th century aether theories.

Obviously metaphors aren't going to be perfect. That's almost always the case. Instead, they're handy because they capture a particularly interesting subset of something larger, more complicated, and get that across by drawing on things a person is already familiar with, like, of course, molasses. Through history, this has progressively become harder to do, and scientists themselves have taken note of it from time to time. For example, Werner Heisenberg delivered a speech in 1932, while receiving the Nobel Prize for physics, in which he pointed out the need to discard visualisation or, more accurately, visualisability as a means to unravelling the pending mysteries of atomic physics. He said it quite eloquently, so let me quote him:

… the path so far traced by the quantum theory indicates that an understanding of those still unclarified features of atomic physics can only be acquired by foregoing visualization and objectification to an extent greater than that customary hitherto. We have probably no reason to regret this, because the thought of the great epistemological difficulties with which the visual atom concept of earlier physics had to contend gives us the hope that the abstracter atomic physics developing at present will one day fit more harmoniously into the great edifice of Science.

This said, metaphors and analogies vis-à-vis quantum mechanics (getting quantum computing right took considerable effort, for a famous example) have become particularly problematic because this field of study has created technologies that are beginning to enter the public consciousness at large. There is now a greater price to pay by misunderstanding, for example, that quantum teleportation refers to bulk matter, as in Star Trek, rather than to information or, in fact, that entanglement is in Albert Einstein's words "spooky action at a distance". But it's not spooky; it's just something we don't have the language for.

But quantum mechanics and its consequent technologies don't have a monopoly on being shortchanged by imprecise communication. Climate change is in the same boat. There is also another kind of price that has already been paid across the vast majority of science: a widespread belief among certain (sadly prevalent) groups of people that they understand science when they really don't, leading to an inflated belief in the abilities and importance of science while overlooking our tendency to confuse faith for truly knowing something. (I have written about this before here, here, and here, among other instances.)

Finally, the question of the gaps between language as we use it and quantum mechanics is reminiscent of a plot point in China Miéville's Embassytown, where people designated "ambassadors" can only speak in pairs, simultaneously: each ambassador utters a different word-meaning, and their alien interlocutors combine the duo's words-meanings to understand what they're saying. In the book, these two word-meanings are written like a fraction – one word on top, a line in the middle, and the other at the bottom. But thanks to Miéville's prose, we know that that's only a partial representation of what's really going on in the story. We come upon a relatable sensation in the film Arrival.

Embassytown was a gratifying read that delved into the relationships between language and storytelling as much as between a language, its grammar, and its symbols. Like good fantasy fiction, it steadily yet gently dismantles the cognitive dissonance that reality sometimes foists on us – in this case, that would be cognising why English or for that matter any linear human language will always fall short of describing true simultaneity.

One workaround, according to the Physics World article above, is that rather than trying to bend our language around the barely tractable and math-laden processes of quantum mechanics, we should describe the field in terms of its outcomes. To know more, do read the article.