Arthur Charlesby—Philosophy and quantum theory

Martin Strauss

Yutaka TANAKA

Catherine Chevalley

Alan M Calverd

Arthur Charlesby opened an interesting debating topic (Letters, January p15). I wonder if I may go some way to closing it?

G. Thompson

A number of matters arise in reply to Arthur Charlesby's letter (January, pl5). Of most importance to physicists: the uncertainties involved in the decay of 60Co can directly and very successfully be ascribed to the uncertainties introduced by the quantum theory. The apparent discrepancy with the scale of Planck's constant, which has the physical dimensions of energy multiplied by time, is completely understandable within the Heisenberg uncertainty principle as being due to the very lack of uncertainty in the mass, and hence energy, of the parent cobalt nucleus.

Jeremy Butterfield, Constantine Pagonis

Physics is a vast discipline, rich with topics inviting philosophical analysis. In undertaking that analysis, the philosophy of physics can be pursued in different styles. There is a spectrum: ranging from the ‘theorem-proof’ style as used in expounding a piece of mathematical physics (though here the theorems will be motivated by philosophical ideas), through philosophical-cum-physical argument that adverts in detail to pieces of physics (e.g. in displayed equations), to purely philosophical argument that is in some way based on, or influenced by, physics. For the most part, the essays in this collection are examples of the second of these three styles: they aim to combine detailed presentation of some technicalities in theoretical physics with the dialectical rigour of analytic philosophy. The essays also have, with one exception, a common subject-matter: the philosophy, or if you prefer foundations, of quantum theory. The first six essays fall squarely in that subject-matter. The seventh and eighth broaden the discussion: they address, respectively, philosophical aspects of (i) the search for a theory of quantum gravity, and (ii) quantum theory's use of group theory. The final essay, by Abner Shimony, is much more speculative: it assesses the conjecture that the fundamental laws of nature are products of evolution. Arthur Fine's essay starts the volume, on a central topic in philosophy of quantum theory: proofs of quantum nonlocality. Fine analyses a proof by Lucien Hardy, which as Fine says, is a characteristic example of a new generation of proofs that apparently make less use of probabilities and thereby dispense with inequalities. However, Fine shows that this appearance is misleading.