Culture and Particle Physics

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CULTURE AND PARTICLE PHYSICS

To seek to understand the basic constituents out of which the great variety of the physical world is made is an intellectual quest of deep significance. The enterprise is as old as the speculations of the presocratic philosophers, such as Thales and Anaximenes, who suggested that there might be a limited number of kinds of fundamental stuff out of which the world around us is made. Two and a half millennia after this kind of thinking began, we have found that the answer is very much more interesting than the simple possibilities, such as fire, earth, air, or water, that occurred to those early thinkers. Any educated person imbued with intellectual curiosity should want to learn about the discoveries that have been made concerning the constitution of matter. Yet some people seem content simply to suppose that "atoms" is an adequate answer, despite those atoms being, from the point of view of people who know about quarks and gluons, systems that are large and composite. Such an attitude of indifference amounts to self-imposed cultural deprivation. It also poses problems for particle physicists, who have to depend upon the good will of the taxpayer for the large sums of money necessary for the pursuit of their research.

History

In 1945, at the end of World War II, particle physics began to move into its Big Science mode, as accelerators and detectors of increasingly larger size and greater cost began to become indispensable means for further advance. The leaders of the experimental community had learnt the value of teamwork from such wartime cooperative experiences as the Manhattan Project, and they had also earned the gratitude of government for their substantial contributions to the war effort. Initially, therefore, funding was comparatively easily obtained but, as the sums requested began to rise steeply, this period of financial honeymoon came to an end. Eventually it became necessary to work collaboratively on an international scale, if sufficient resources were to be available. The consortium of European nations that has made the European Laboratory for Particle Physics (CERN) possible is an outstanding example of the fruitfulness of enterprises of this kind, demonstrating to the world that collaborations of such wide scope can be successful and need not succumb to the disrupting effects of national rivalries.

In their appeal to the taxpayer for finance, particle physicists can point to the pragmatic usefulness of some of the spin-offs from their work. The construction of precision engineering devices operating on kilometer scales has required the development of techniques that have proved to have applications beyond the control system of a synchrotron or storage rings. At the same time, many talented young people have served scientific apprenticeships within the high-energy physics community and gone on to make use of the talents, skills, and experience they acquired in other fields of application. Yet these are merely collateral arguments for the support of particle physics.

The fundamental justification for the activity of the subject lies in the intrinsic intellectual value of uncovering and understanding the substructure of the physical world. As the American accelerator builder, Robert Wilson, said, when questioned by a senator about what the latest project for which he was seeking funding would do for the defense of the United States, "Nothing—but it will help to make the United States worth defending!" The heart of the cultural case for particle physics is that it affords us knowledge of a kind that, in its depth and fundamentality, is the source of its own intrinsic value. Yet particle physicists face a number of problems in conveying this truth to the general educated public.

Cultural Problems

One problem is the lack of pictorial appeal in the visual material of particle physics. The contrast with the cosmologists—those other fundamental scientists who are operating at the other end of the length scale—is striking. Astronomical pictures, such as the deep space photographs taken with the Hubble space telescope, are often breathtakingly beautiful and immediately seize the public imagination. On the other hand, the average bubble chamber photograph, or a diagram of spark discharges in a detector, is frequently messy and unappealing. Only when these weird patterns are interpreted do they reveal their fascination and stimulate the viewer's interest. Few outsiders, however, will persevere in penetrating far enough into the subject to be able to make this discovery.

Another problem arises simply from the minute scale on which the phenomena of particle physics take place. Everyone has looked up at the starry heavens and wondered what is going on there. Few people are disposed to look inward at the structure of matter in a similar way. Genes in the case of living beings, and atoms in the case of inanimate entities, is about as small as many are prepared to go.

A third difficulty, endemic in physics as a whole but particularly acute in the case of particle physics, is the essential role of mathematical thinking. Paul Dirac expressed his conviction that the fundamental laws of physics are expressed in beautiful equations, illustrating this fact in striking fashion by his discovery of the relativistic equation of the electron. Yet mathematical beauty is a rarified aesthetic experience which comparatively few are privileged to share. The intellectual attractions of gauge field theories, let alone the rarified delights of string theory, are inaccessible to those who have to rely on words alone to receive the message.

Perhaps a fourth difficulty has arisen from the inevitable development of huge experimental groups, involving literally hundreds of Ph.D. physicists in their activities. The work is necessarily fragmented and distributed to many subgroups, inhibiting the possibility of telling a story of bold simplicity centering on the work of a single vivid personality. This prevalence of group activity has also encouraged the suspicions of contemporary sociologists of knowledge. The so-called science wars have been about whether science is discovery at all, but rather it is asserted that theories are simply the tacit agreement of a like-minded in-group (the invisible college of particle physicists) to see things this way. On the contrary, scientists, not the least of which particle physicists, are very conscious of how surprising nature frequently turns out to be, frustrating initial expectations and forcing conclusions that are more intellectually satisfying than the scientists could have anticipated beforehand. This experience seems to physicists only to be credibly explained in terms of discovery and not mere construction. If postmodern culture were to succeed in casting doubt on the attainability of a verisimilitudinous mapping of the physical world by science, this would have serious consequences for the health of particle physics and for an honorable interest in its activities. After all, what would be the point of so much expenditure of effort, talent, and money if it were not telling what matter is really like? The physical regimes created in high-energy experiments are very extreme, far from situations likely to be of direct relevance to the processes of everyday life. Their significance is fundamental and not simply pragmatic.

Cosmic Questions

The regimes investigated in modern accelerator experiments are relevant, however, to the state of matter at the beginning of the observable universe. A fusion of cosmology and particle physics is necessary for the discussion of the very early cosmos and this has enabled particle physics to acquire some of the glamour associated with cosmology. One of the most astonishing impacts of science upon general culture observed in recent years has been the multi-million-copy sales of Stephen Hawking's A Brief History of Time (1988). Partly, no doubt, this has been due to respect for the remarkable character of its author, but this success was also clearly fueled by a feeling that to know something about the fundamental history and nature of the physical universe is to know something of real value and significance. Yet one must also acknowledge that all theories of quantum cosmology are not only doubly difficult to expound, combining the need to explain both quantum theory and general relativity, but also, pending the full reconciliation of these two great discoveries, dependent on a precarious degree of intellectual conjecture.

A profound cultural consequence of particle physics is the recognition that the universe is both rationally transparent to human inquiry (in that people are able to penetrate the secrets of the subatomic world, despite its nature being so counterintuitive when compared with the world of everyday experience) and also rationally beautiful to an astonishing degree (those beautiful equations). The fact that particle physics is possible at all is surely a highly significant fact about reality. Human thought has proved able to access and understand processes taking place on extremely short length scales and, when that understanding has been gained, it has proved to be of a kind that excites wonder in those privileged to participate in it. A particle physicist will instinctively doubt a theory that does not display the recognizable, if abstract, character of mathematical beauty. Part of the current dissatisfaction with the Standard Model is that its possession of so many adjustable parameters denies it that elegance and economy that scientists have come to expect as the hallmark of a truly fundamental theory. Physicists believe that this stance is no mere attitude of mathematical aestheticism, for the use of these nonempirical criteria as techniques of discovery and as indicators of validity has proved itself time and again in the history of physics by the long term fruitfulness displayed by resulting theories of this kind. Dirac's discovery of the relativistic equation of the electron, and Albert Einstein's discovery of the equations of general relativity, are cases in point. These considerations, together with the intrinsic interest of the questions it addresses, give particle physics a secure and significant place in the cultural attainments of humankind.