Quantum Theory and Relevant Education
I recently re-read a most fascinating book: Edwin Arthur Burtt's Metaphysical Foundations of Modern Physical Science, published in 1924. This classic was last republished in 1980 and is available from Humanities Press International, 165 First Avenue, Atlantic Highlands, NJ 07716-1289, phone 908-872-1441 ($15, paperback).
Letting the principal players, Copernicus, Kepler, Galileo, Descartes, Newton, and others, speak for themselves, Burtt recounts the transition from the medieval to the Newtonian worldview. Burtt's analysis makes clear, if it wasn't already, that Newtonian physics reformed not only science but also the entire philosophical foundation of European culture during the 16th through the 19th centuries. The "clockwork universe" framed the worldview of the creators of European culture during those centuries. It is a worldview that continues to powerfully influence western thought in ways both direct and indirect. We still live in the Newtonian age.
Burtt sees "need for a critical, historical study of the rise of the fundamental assumptions characteristic of modern [post-medieval] thinking," and sets out to begin filling this need. More recently, Arthur Koestler took on a similar task in The Sleepwalkers, a more poetic but more dogmatic and less compelling work than Burtt's.
The theme that emerges is that the giants of Newtonian physics did not take their philosophy sufficiently seriously, and that western culture has for many centuries accepted the mechanical universe uncritically, without serious analysis of its validity or consequences. In Koestler's metaphor, we have "sleepwalked" into a worldview that might or might not be valid, that might or might not be healthy, but that has assuredly dominated industrial societies for centuries.
One science-and-society lesson that I take from this is that our scientific worldview is more important, socially, than we might have thought. If so, we should take the philosophical and cultural implications of science far more seriously than we do. It is a delusion to argue that physics has no philosophical impact, or that physicists should refrain from philosophy. Everything has philosophical impact, science most of all today, and the only question is whether that impact will be conveyed thoughtfully, or thoughtlessly.
In particular, we physicists should do more to communicate the meaning of physics, and its possible cultural impact. Our textbooks and our lectures, so full of formulas, techniques, and problems, pay much attention to getting the "right answer," and little attention to the ideas. But it is the ideas that count. Physics is, after all, about understanding ("standing beneath") nature, not about manipulating her.
The most glaring example is "quantum mechanics." The very term, an oxymoron if there ever was one, indicates our lack of interest in the theory's meaning. Quantum theory is our most general, and most accurate, conception of the natural world. So far it has worked perfectly. Yet the entire topic gets crowded into a week or two of introductory physics, following nearly a full year of Newtonian physics. And in those few lectures it is the most Newtonian topics, such as the Bohr atom and the photoelectric effect, that get the most attention.
This is a matter of some societal significance, because scientific worldviews have social impacts. At least in our teaching, we continue the sleepwalk that perpetuates Newtonianism. The universe is quite non-Newtonian, but few students coming out of two-semesters of introductory physics would suspect any such thing. In a course that includes among other things a week on torque, a week on statics, a week on geometrical optics, a week on alternating currents, and a week on quantum theory, students come away believing that all these are of equal significance, and that quantum theory is just a small correction to Newtonian physics.
Shouldn't students come out of some 90 contact hours of physics "lecture" and 90 hours of lab with a rough idea of how the universe actually works? For example, how it started, its general shape, what it is made of, and how its parts change and interact? In our teaching of technique, understanding has nearly vanished into the calculational fog.
Topics that illuminate quantum theory include the double-slit experiment with matter and with radiation, wave-particle duality, the meaning of the wave function, Schroedinger's equation as an idea (students don't need to use it--they need to know about it and see a few solutions), quantum uncertainties, the uncertainty principle, Bell's theorem, non-locality with examples such as Aspect's experiment, the debate about hidden variables, and the measurement problem including collapse of the wave function, the role of the observer, observer-created reality and Schroedinger's cat. For good books on these topics, see Nick Herbert's Quantum Reality (Anchor Press, Doubleday, New York, 1985), and Jim Baggott's The Meaning of Quantum Theory (Oxford University Press, New York, 1992). And see N. David Mermin's articles in Physics Today.
There is no reason not to teach students, without the equations but with the concepts, the full quantum theory of a universe made of interacting quantized fields. Some will say that we can't teach such topics without the proper math. I don't believe it. Richard Feynman, for one, believed that if you can't teach some specialized technical topic, such as your own research, to an intelligent non-mathematical non-scientist, then you don't understand your topic.
If you are a teacher, then you have probably noted by now that there is at least one slight problem with all of this: time. How can any of this be accomplished, in already-bloated introductory courses, especially when some very good physics educators such as Arnold Arons urge us to devote even more attention to Newtonian accelerations and forces in order to deal with student learning difficulties? Good question.
The Introductory University Physics Project is one attempt to deal with this question. It has made many good suggestions. I would suggest devoting much less time to technique and more to concepts, and dropping less-than-fundamental topics such as torque, angular motion, statics, electric circuits, and geometric optics. And do we still need the Bohr atom?
But this approach probably doesn't go far enough, because it starts from the present course and asks "how can we improve it?" Instead of improving on the present course, perhaps we need to start over and ask what we really want to communicate, and invent a course that does it. If our goal is to communicate science's view of nature, then I'm certain we can find a way to do it, with enough calculations included to satisfy any reasonable desire for developing students' technical skills, in 90 contact hours. But we need to start with that goal, and then decide what we should and could teach toward that goal.
Physics is not about this or that technical problem. Physics is about understanding nature, and it is ultimately about ourselves. The point is not just "academic." Four centuries of the clockwork universe testify that this point is socially significant.
Art Hobson