Robert P. Crease and Alfred Scharff Goldhaber
The Quantum Moment
W.W. Norton & Co., 2014
In his 1959 lecture ‘The Two Cultures’, C.P. Snow remarks the gap between “men of science” and “men of letters” (they’re all men in 1959, it seems). After running through the literary ignorance of the scientists of his acquaintance, he goes on to claim that the converse holds true as well:
But what about the other side? They are impoverished too—perhaps more seriously, because they are vainer about it. They still like to pretend that the traditional culture is the whole of ‘culture’, as though the natural order didn’t exist. As though the exploration of the natural order was of no interest either in its own value or its consequences. As though the scientific edifice of the physical world was not, in its intellectual depth, complexity and articulation, the most beautiful and wonderful collective work of the mind of man.
At a first glance, The Quantum Moment, written by the philosopher-and-physicist duo of Robert P. Crease and Alfred Scharff Goldhaber, sets out to show (or perhaps presupposes) that Snow’s judgment no longer holds. “The discovery of the quantum…planted a rich set of metaphors in the popular imagination. Quantum imagery and language now bombard us like an endless stream of photons…reinterpreted by each new generation of artists and writers,” the blurb urges, with the result that “understanding quantum language and imagery, and recognising its misuse, is part of what it means to be an educated person today.” Thus, Crease and Goldhaber set out to trace how ideas from quantum physics—the physics appropriate for describing matter’s behaviour at small length-scales, notorious for its mind-bending implications—have been incorporated into a broader cultural story.
Upon closer examination, however, their investigation turns out to deliver a much more ambiguous verdict. The strongest testament to the continuing grip of Snow’s split is perhaps to be found in the form of the book rather than its content. The chapters, each discussing how a quantum idea has filtered out into mass culture, are followed by “interludes” that describe the underlying physics (and the history thereof); an easy acquaintance with the science isn’t something that can be assumed, any more than it was in Snow’s day. And as the book goes on, the examples of quantum-inspired works that Crease and Goldhaber draw upon form an eclectic assembly: the young-adult novel Will Grayson, Will Grayson, the writings of John Updike, the webcomic xkcd, and many more besides. But although plenty of individual artists have appropriated or exploited quantum terminology, one doesn’t get the sense of a general cultural shift induced by the quantum revolution—certainly not in the way that, as Crease and Goldhaber outline in their first chapter, Newton’s work helped to inform and structure the worldview inhabited by early modern thinkers.
Nevertheless, this doesn’t rule out a more modest cultural life for the quantum: one where rather than providing a general architecture in which a society’s discourse might live, it can still prove a rich source of powerful images or arresting metaphors. And several of the examples they discuss do make effective use of such imagery: for example, Updike’s vision of a world governed by continuous, rational dynamics when viewed at a sufficiently coarse grain, but whose micro-workings seem to baffle scrutiny, does articulate how many of us might feel about the social world. But one might wonder how much work the analogy to quantum physics is really doing here: even in classical physics, the dynamics of a stream is apt to be more readily comprehensible than the motion of its individual molecules.
On the converse, the more distinctively “quantum” the metaphor—the more recondite the physical principles it draws upon—the harder it will be to make it do illuminating work. The point of a metaphor, after all, is usually to help clarify something: a potentially tricky emotional situation, or a subtle intellectual concept, is made intelligible and vivid by analogy to something familiar and concrete. But this does mean that metaphors tend to work less well when the material they are drawing upon is at least as unfamiliar and difficult as that which it is being exploited to explain. In other words, it is (to put it mildly) somewhat unclear what the value is of comparing one’s own emotional state to that of an entangled particle if this needs to be followed by a very slow and careful explanation of what “entanglement” means. If anything, the metaphors are apt to get sucked into operating in the other direction: we end up using the metaphor of emotion to help us get a grip on entanglement, not the other way round. This isn’t universally true, of course: within a subculture that can be assumed to be sufficiently familiar with such phenomena in their original context, such a metaphor might well be helpful. But the residual oddness of such a comparison is apt to remain, which may help explain the bittersweet potency of “geek comics” such as xkcd (“a webcomic of romance, sarcasm, math and language”). And even scientists, confronted with a theory possessing the prima facie weirdness of quantum mechanics, may prefer to use their cultural interests to understand the science rather than vice versa: Crease and Goldhaber discuss how Bohr reached to the emergent Cubist movement for inspiration in articulating his philosophy of quantum “complementarity”.
The other difficulty in applying quantum concepts to the social world is that in order to be helpful to artists who aren’t scientifically trained, these concepts need to be given a non-mathematical gloss—and in the case of a theory such as quantum mechanics, whose interpretation remains a matter of huge controversy, such glosses run the risk of disguising contentious philosophical questions as matters of scientific fact. Unfortunately, the authors’ treatment of quantum mechanics’ philosophical controversies is somewhat dogmatic. They are fans of Bohr’s approach, which draws heavily on the notion of “complementarity”: roughly, the idea that seemingly inconsistent or contradictory natures (like being a wave and a particle) may be potentialities of one and the same entity (say, an electron), such that which one is actualized depends upon the nature of the experiment one chooses to perform. Bohr’s representations of this idea are notoriously cryptic—the authors quote Popper’s remark that “I do not doubt that there is an interesting intuitive idea behind Bohr’s principle of complementarity. But neither he nor any other member of this school has been able to explain it.” In spite of this, Crease and Goldhaber have some interesting remarks about how this idea might be spelled out more intelligibly, notably by drawing upon phenomenology.
This is all to the good, but doesn’t excuse the short shrift given to other interpretations. Hidden-variable theories, such as the de Broglie-Bohm theory (which takes the wavefunction to be a causal mechanism responsible for the motions of the—ontologically distinct—particle) are mentioned only in passing, whilst dynamical collapse theories (which postulate physical mechanisms to explain just how an electron’s potentialities are reduced to a single actuality) don’t even merit a mention. The Everett, or “many-worlds”, interpretation gets a somewhat longer discussion, in virtue of the ubiquity of parallel worlds in pop culture. But it’s derided as a “cheat”, and chided for its failure to appreciate that the wave function is merely “an instrument of prediction…as a calculational tool, it does not mean that the system really is in all those states, only the probability that each one will become real”—less a refutation, than a mere re-assertion of Bohr’s own view. More generally, there’s just a worrying level of complacency about how difficult it is to interpret quantum mechanics. Those hesitant about an irretrievably observer-dependent notion of reality are, we learn, merely those who haven’t noticed that quantum mechanics has helped “rid philosophy…of the vision…of an impossible objectivity”—news which will come as something of a surprise to those philosophers who are not advocates of phenomenology. This is more than just philosophical sniping, since it is this (alleged) impact on our philosophical worldview that Crease and Goldhaber claim as Exhibit A for their contention that, were it not for quantum mechanics, the humanities would be decidedly impoverished. If quantum mechanics does admit of more robustly realist interpretation, then more work is needed to show that it validates, or that it precipitated, wider intellectual shifts towards this kind of postmodern thought.
Ultimately, The Quantum Moment doesn’t quite fulfil the ambitions it sets out with: the cultural impact of the quantum turns out to be more attenuated and scattered than the authors suggest. But in the process of sketching out that impact, they deliver a very enjoyable and well-written account of quantum physics—one which, to its credit, engages with quantum theory’s historical background much more closely than most pop-science accounts.
Ironically, perhaps, by exploring how ideas from quantum mechanics are applied in other media, Crease and Goldhaber equip themselves remarkably well to explain how those principles apply in physics itself. Aided by an admirably clear prose—and a judicious willingness to skip over details posing excessive expository difficulties—we obtain a very nice account of the key concepts in quantum mechanics, and of the processes and personalities that brought them into being. If the cultural history of quantum remains to be written, it is because quantum ideas remain largely inaccessible to the culture at large. If nothing else, The Quantum Moment goes some way towards making them less so.
Neil Dewar  is reading for a DPhil in the philosophy of physics at University College, Oxford.