Concept Summary      Chapter 8

One of the major scientific questions of the twentieth century seemed so simple. What are electrons, photons, and other subatomic objects that made the amazing technological revolution of this century possible? After more than 80 years of asking this question, no consensus on an answer has been reached, and widely divergent views on the nature of reality and the role of science in dealing with reality have resulted.

Experiments with subatomic phenomena show effects that are difficult to reconcile with our normal view of an objective world. Particles of matter are independent objects that are located in one place at a time. Waves can spread out and/or split and be in many places at the same time. All experiments with subatomic phenomena show wave-particle duality; rather than a definitive, objective world, reality seems to be ambiguous at the quantum level.

Although a very successful mathematics was developed enabling physicists to interact with, explore, and extend applications of subatomic reality, the interpretation of the mathematics is a philosophical muddle. One of the most influential interpretations of quantum physics was that of Niels Bohr and what has come to be called the Copenhagen interpretation. According to this interpretation, the ambiguity and complementarity of quantum experimentation reveal a startling pragmatic, epistemological discovery: Our macroscopic experiments must be conducted from the point of view of a human conceptual reference frame, but nature at the quantum level need not, and apparently does not, conform to macroscopic concepts. Accordingly, what we measure in our quantum experiments are the results of our relationship with nature, not nature itself. Between moments of preparation and measurement of quantum events, there is nothing definitive to know, understand, or measure, because nature has revealed to us that there is nothing there that can be conceptualized in human terms. Subatomic phenomena such as photons and electrons become definitive objects only after measurements are made with macroscopic equipment.

Because Einstein was convinced that the job of science is to reveal the clockwork mechanism of nature itself, not just the probabilistic results of our relationship or experimental tinkering with nature, he objected to this interpretation. Quantum theory could not be a complete theory. For Einstein there was an underlying reality that we did not understand yet; for Bohr, the goal of knowing an underlying, definitive reality was a antiquated philosophical relic of classical physics. For Einstein, the Copenhagen interpretation implied defeatism at its best and classical idealism at its worse. For Bohr, many fruitful explorations still exist, relationships yet to be described and mathematical trails yet to be followed, but the search for a "hidden" reality will not be one of them.

The work of Bell and Aspect resulted in a strong experimental confirmation that in the quantum realm it is wrong to think of quantum phenomena as independent hidden entities influenced by independent local circumstances. Like Newton confronting the problem of gravity, most physicists in this century have been trained to adopt a pragmatic or instrumentalist stance to these results -- science is suppose to describe the objective properties of experiments, not to speculate on a hidden reality between measurements. But the compelling need for a philosophical understanding produced numerous proposals.

Some physicist-philosophers argued that the success of quantum theory shows that far from being a secondary quality, consciousness has a major causal role in the universe; it produces a definitive, relationship-reality from an ambiguous, featureless whole. David Bohm suggested that an interpretation of radical neorealism is still possible, one which describes a multidimensional hyperspace of implicate wholeness "behind" the explicate or definitive reality of our common-sense world. Others argued that a rigorous interpretation of the mathematics of quantum theory reveals that the divergent results of interactions with the quantum realm can be explained in terms of real, branching or splitting universes. Still others claimed that we must abandon traditional realism altogether. The world cannot be pictured as "sitting out there" for us to uncover; our "participation" with an intermingled dance of possibilities yields a concrete reality. Finally, some even claimed that quantum theory represents a convergence of Western and Eastern philosophies; modern science has uncovered the same indescribable, interconnected oneness discussed by mystics for centuries. For the mystic the result of quantum experiment is like a man with a torch surrounded by darkness. The man wants to experience the darkness, but keeps running senselessly at the darkness with his torch still in hand. Many Western trained scientists believe this is total nonsense.

One thing seems clear. There are plenty of mysteries left to stimulate the next generation of physicists.