By W. H. Watson London: Cambridge University Press. 1963. Pp. xiii + 218. Price 30s. In this book Professor Watson deals with a major question which has been worrying scientists for some time, namely why it is that physics continues to go from strength to strength with scarcely any philosophic support worthy of the name. In fact, taking the particular case of the part played by metaphysics, we are left in considerable confusion, especially in regard to the most profound aspects of quantum mechanics.
By W. H. Watson London: Cambridge University Press. 1963. Pp. xiii + 218. Price 30s. In this book Professor Watson deals with a major question which has been worrying scientists for some time, namely why it is that physics continues to go from strength to strength with scarcely any philosophic support worthy of the name. In fact, taking the particular case of the part played by metaphysics, we are left in considerable confusion, especially in regard to the most profound aspects of quantum mechanics.
There are several (general) philosophy of physics textbooks on the market.1 An
obvious question to ask at the outset then is: Why another one? In his “Some
Philosophical Aspects of Particle Physics”, Michael Redhead bemoans the common practice of philosophers of science of dealing with examples “which are no
longer of current research interest in science” ((1980), p. 279). This practice is
still common even among many philosophers of physics, and, for the most part,
the available textbooks continue to engage in this practice. Generally, one finds a
little spacetime, a little statistical mechanics, and a little quantum theory. Now,
these are of course the ‘pillars’ of modern physics, so it is what we should expect
to be covered in any textbook on the philosophy of physics worth its salt (and,
indeed, they are well represented in this book). However, the issues that are
dealt with are usually very old fashioned and very limited in scope: ‘spacetime’
means ‘the twins paradox’ (and possibly conventionalism); ‘statistical mechanics’
means ‘time asymmetry’; and ‘quantum theory’ means ‘the measurement problem’. Redhead is surely right that this leads physicists to “regard philosophy of
science as somewhat irrelevant”. Rightly so, too, if this were in fact representative of much of what actually goes on in philosophy of physics. However, the
state of play as represented in philosophy of physics and (some) philosophy of
science journals shows a very different level of engagement, with philosophers
of physics investigating the frontiers of scientific research. This disparity (or the
impression of such) is the raison d’eˆtre for the book you are now reading. The result is an introductory textbook covering those portions of philosophy of physics
research that other textbooks fail to cover, or cover only very briefly or very
simplistically. The three pillars of modern physics-relativity, quantum theory
and statistical mechanics-are still represented, then, but from a more advanced
and contemporary perspective.
The relation between Physics and Philosophy brings to mind the proverbial marriage of high drama; the parties do not approve of each other, but separated they cannot live. Philosophers find physicists shallow, and many physicists claim that they find philosophic speculations useless or worse. Mostly both display a lack of knowledge and understanding of the methods and goals of the other. A few researchers have tried to bridge this gap and explore the worlds of both parties. Michael Redhead has worked in this borderland, and when he retired from his chair in Cambridge, a symposium was arranged to honour him. The talks presented on this occasion are now published in a volume presenting much food for thought to both philosophers and physicists. The essays in this publication do not offer easy reading; not too many readers will have the preparation to penetrate the technical arguments offered. The authors are well acquainted with both philosophical argumentation and mathematical formalism, and, following the lead of Professor Redhead, they combine these in intricate and suggestive ways. Only a close reading can offer understanding of the points of view taken by the various authors. Browsing and mere reading defines the scenery, exploring it demands much more. Many of the nine essays included investigate the meaning of terms used loosely in physics contexts: locality, beables, symmetries and time in relativity. All essays utilize the mathematical structures of physics, but the approach is mainly philosophical; concepts like reality and metaphysics are applied. Some writings are more physical in their treatment of technical questions relating to modern quantum theory. Bohmian mechanics, localized quantum states and gauge symmetries are discussed in detail. It is, however, found that these present interpretational problems that are usually glossed over in purely physical treatments. For an old sceptic like myself, it is quite refreshing to find that many assertions, taken for granted in our textbooks, are indeed doubtful and offer conceptual or technical difficulties. This insight is what a philosophical analysis can offer the working physicist; future progress may well arise from such realizations. However, the results offered by philosophical analysis are usually found unsatisfactory; the hope that philosophy can suggest novel directions for the theory remains unfounded. Philosophers can learn that modern physics rests on a very shaky conceptual foundation. The theory has evolved by a combination of serendipity and opportunism. The beast that finally has emerged is neither well founded nor internally consistent. Its only merit is that it works. That offers the ultimate philosophical problem of modern physics. If the present book can help the philosopher to behold this challenging but overwhelming wilderness, then it serves a useful purpose indeed. But the prospective researcher has to learn to master the difficult language used by the natives, who are not always friendly. I enjoyed reading the book immensely, but the technical difficulty of the text made my understanding remain mostly superficial. I hope to have the time to return some of the essays, and look into the references and issues involved. The work is genuinely what it promises: a guide From Physics to Philosophy .
THE conceptual problems raised by the discovery of quantum effects have not been fully resolved after half a century. Part of the reason for this is undoubtedly to be found in the mutual ignorance which prevails between physicists and philosophers. In his book Heisenberg brings together a philosophically inclined temperament with an unrivalled knowledge of physics. The result is a book of very great interest, however much one might disagree with his conclusions. The collection of essays of which the other book is made up is intended to bring crucial conceptual problems in physics especially to the notice of philosophers. The design and intention of the collection is admirable for this is the proper way to overcome the departmentalization of interest that has left the deep conceptual problems still unresolved. Men like Heisenberg who combine philosophical temperament with scientic knowledge of great distinction are rare, and yet the difficulties can only be cleared up by the application of philosophical techniques of analysis to problems which are an intimate and difficult part of physics. A great deal of the interest of Heisenberg's book lies in the very comprehensive account he gives of the origin and growth of the Copenhagen school, and the way the new phenomena forced a largely unwelcome picture of nature upon Bohr and his friends. The most important chapter from a philosophical point of view is that in which Heisenberg defends this interpretation against the attacks to which it has been subjected. The essence of his argument for the interpretation can be summed up in two propositions. (i) The Copenhagen interpretation of physical theory, which depends upon the acceptance of the so-called Principle of Complementarity, is an inevitable and final interpretation. The reason for this is that there are only two possible general models for understanding given physical phenomena; a particle model or a wave model. These are exhaustive and exclusive because the former depends upon discontinuous and the latter upon continuous (using substance here in the traditional philosophical sense). If we find, as we do, that the two fundamental constituents of the universe, matter and radiation, each exhibit two classes of phenomena, one explainable only on a particle model and one on a wave model, then we are compelled to adopt a complementarity hypothesis and give up the idea of finding a single and uniform model for the understanding of phenomena. There are only two kinds of models; they are mutually exclusive; both are required; hence we either despair before an insoluble problem or adopt the Copenhagen interpretation. (2) Any serious criticism of this interpretation must offer an alternative
J M Ziman London: Cambridge University Press 1969 pp xii + 269 price £2.75 The days are long since past when a knowledge of the Schrödinger equation, or perhaps even of the Dirac formalism and the algebra of Hilbert space, was sufficient equipment to enable theoretical papers on aspects of quantum theory to be read and understood. Today one is faced with the symbols and concepts (field operators, Feynman graphs, Green functions, the S matrix, and so on) of what to many must seem an inaccessible world.