On Wheeler's notion of “law without law” in physics

JOHN ARCHIBALD WHEELER

Anton Zeilinger

Introduction First a word of thanks. When I first came across the papers of John Archibald Wheeler on the foundations of quantum mechanics, most of them reprinted in Wheeler and Zurek (1983), I could not believe what I read. Finally here was a colleague of worldwide reputation, given his many contributions to theoretical physics, who was not afraid to discuss openly the conceptual problems of quantum mechanics. The outstanding feature of Professor Wheeler's viewpoint is his realization that the implications of quantum mechanics are so far-reaching that they require a completely novel approach in our view of reality and in the way we see our role in the universe. This distinguishes him from many others who in one way or another tried to save pre-quantum viewpoints, particularly the obviously wrong notion of a reality independent of us. Particularly remarkable is Professor Wheeler's austerity in thinking. He tries to use as few concepts as possible and to build on this the whole of physics. A fascinating case in point is the title of one of his papers “Law without law,” the attempt to arrive at the laws of nature without assuming any law a priori. For me personally his work on fundamental issues in quantum mechanics has been particularly inspiring. The questions he raises are exceptionally far-reaching and some of his concepts in the foundations of physics are so radical that calling them revolutionary would not do them justice.

Stefan Wolf

Landauer's principle claims that "Information is Physical." It is not surprising that its conceptual antithesis, Wheeler's "It from Bit," has been more popular among computer scientists --- in the form of the Church-Turing hypothesis: All natural processes can be computed by a universal Turing machine; physical laws then become descriptions of subsets of observable, as opposed to merely possible, computations. Switching back and forth between the two traditional styles of thought, motivated by quantum-physical Bell correlations and the doubts they raise about fundamental space-time causality, we look for an intrinsic, physical randomness notion and find one around the second law of thermodynamics. Bell correlations combined with complexity as randomness tell us that beyond-Turing computations are either physically impossible, or they can be carried out by "devices" as simple as individual photons.

Valia Allori, Nino Zanghı̀

Ravi V. Gomatam

Steven Weinberg writes, “Einstein rejected the notion that the laws of physics could deal with probabilities, famously decreeing that God does not play dice with the cosmos. But history gave its verdict against Einstein—quantum mechanics went on from success to success, leaving Einstein on the sidelines.”Einstein did not reject quantum theory merely because it is probabilistic. He wrote: “There is no doubt that quantum mechanics has seized hold of a beautiful element of truth, and that it will be a test stone for any future theoretical basis.” 1 1. A. Einstein, quoted in J. Wheeler, W. Zurek, Quantum Theory and Measurement, Princeton U. Press, Princeton, NJ (1983), p. 8. Nor was Einstein unilaterally opposed to God playing dice. He expected God to either play dice all the way or not at all. If individual events were totally undetermined, then the overall events should also be undetermined, and not display remarkable regularity. “In for the penny, in for the pound,” he wrote. Thus, a more accurate quote from Einstein about God and dice playing is the following:“That the Lord should play with dice, all right; but that He should gamble according to definite rules, that is beyond me.” 1 1. A. Einstein, quoted in J. Wheeler, W. Zurek, Quantum Theory and Measurement, Princeton U. Press, Princeton, NJ (1983), p. 8. REFERENCESection:ChooseTop of pageREFERENCE <<1. A. Einstein, quoted in J. Wheeler, W. Zurek, Quantum Theory and Measurement, Princeton U. Press, Princeton, NJ (1983), p. 8. Google Scholar© 2006 American Institute of Physics.

Willis H. Truitt