Tim Maudlin

Physics uses mathematical objects to represent physical ontology. Philosophy more often discusses the status of mathematics per se rather than its use as representation. Consequently the gap between mathematical objects and the physical entities they represent becomes obscured. Indeed, these two quite things often go by the same name. The wave function would seem to be a mathematical object. Our concern as metaphysicians is the entity the function represents, which we may call the quantum state. Failure to distinguish these has sometimes led to an overly naive approach to reading off the nature of the entity represented from the structure of the mathematical representation. In particular, it has led to the idea that because the mathematical representation "lives" on a high-dimensional mathematical space, there must exist some corresponding high-dimensional real physical space. Once one appreciates the role of the wave function in the mathematical representation, this supposition is shown to be groundless. What remains is a puzzle about why one would use a function on what looks like the configuration space of a collection of particles unless the theory postulates the existence of a collection of particles.

A common understanding of both the many-worlds theory and the original version of the GRW theory holds that they are ontologically monistic, postulating only the existence of the wavefunction and nothing else. Sometimes an appeal to Occam's razor is used to promote this as a boon for these theories. But without more detailed argumentation, it is hard to see how such an austere ontology can make comprehensible contact with the experimental facts that inspired the development of quantum theory in the first place, or indeed with our whole pre-theoretical picture of the physical world.

This chapter considers three ways in which probabilities may be derived from a physical theory without adverting to subjective considerations. The first derives from a fundamentally stochastic dynamics that implies transition chances at the level of natural law. The second is a Humean approach, in which probabilities are deployed as part of a compact system for conveying information about the structure of the Humean mosaic, i.e. the distribution of local physical quantities in space-time. The last employs either deterministic or stochastic dynamics together with a measure of typicality, i.e. a measure of sets of initial conditions that count as extremely large. Probabilities emerge in this setting as typical frequencies, that is, frequencies exhibited by most initial conditions.

Modern physics was born from two great revolutions: relativity and the quantum theory. Relativity imposed a locality constraint on physical theories: since nothing can go faster than light, very distant events cannot influence one another. Only in the last few decades has it become clear that the quantum theory violates this constraint. The work of J.S. Bell has demonstrated that no local theory can return the predictions of quantum theory. Thus it would seem that the central pillars of modern physics are contradictory.

At least since the work of Tarski, the Liar paradox has stood in the way of an acceptable account of the notion of truth. It has been less noticed that once one admits a truth predicate into a formal language, along with intuitively valid inferences involving the truth predicate, standard classical logic becomes inconsistent. So, any acceptable account of truth must both explicate how sentences get the truth values they have and amend classical logic to avoid the inconsistency. A natural account of a trivalent semantics arises from treating the problem of assigning truth values to sentences as akin to a boundary‐value problem in physics. The resulting theory solves the Liar paradox while avoiding the usual ‘revenge’ problems. It also suggests a natural modification of classical logic that blocks the paradoxical reasoning. This semantic theory is wedded to an account of the normative standards governing assertion and denial of sentence and a metaphysical analysis truth and factuality. The result is an account in which sentences like the Liar sentence are neither true nor false, and correspond to no facts.

Modern physics was born from two great revolutions: relativity and quantum theory. Relativity imposed a locality constraint on physical theories: since nothing can go faster than light, very distant events cannot influence one another. Only in the last few decades has it become clear that quantum theory violates this constraint. The work of J. S. Bell has demonstrated that no local theory can return the predictions of quantum theory. Thus it would seem that the central pillars of modern physics are contradictory. Quantum Non-Locality and Relativity examines the nature and possible resolution of this conflict. Beginning with accurate but non-technical presentations of Bell's work and of Special Relativity, there follows a close examination of different interpretations of relativity and of the sort of locality each demands. The story continues with a brief discussion of the General Theory of Relativity. This second edition also includes a new author's preface and an additional appendix. The book introduces philosophers to the relevant physics and demonstrates how philosophical analysis can help to resolve some of the problems. All of the physics is presented from first principles, and as much as possible is presented pictorially. Book jacket.

Quantum Non-Locality and Relativity is recognized as the premier philosophical study of Bell's Theorem and its implication for the relativistic account of space and time. Previous editions have been praised for the remarkable clarity of Maudlin's descriptions of both Bell's theorem and his examination of the potential conflict between the theorem and relativity. The third edition of this text has been carefully updated to reflect significant developments, including a new chapter covering important recent work in the foundations of physics. Foremost among these is Roderich Tumiulka's explicit, relativistic theory that can reproduce the quantum mechanical violation of Bell's inequality. The "Free Will Theorem" of John Conway and Simon Kochen is also discussed, as is the status of locality in the Many Worlds interpretation of quantum theory. The book has also been updated to reflect recent results in information theory. The book introduces philosophers to the relevant physics and demonstrates how philosophical analysis can help to resolve some of the problems, and requires no technical background in Physics. All of the physics is presented from first principles, and as much as possible is presented pictorially"--Provided by publisher.

Bilim ve felsefe, gerçekliğin doğasını anlamlandırma araştırması olarak betimlenebilir. Hatta bazen bu iki alan karşı karşıya getirilerek, bilimin başarısının felsefenin geçerliliğini baltaladığını öne sürerler. Ancak aranılan türden bir anlayış veya açıklama ile ilgilenmek farklı bir tablo sunar: Uygulandığı şekliyle çağdaş fizik bazen dünyanın net bir fiziksel açıklamasını sağlamakta başarısız olur. Einstein, Schrödinger ve John Bell tarafından ifade edilen standart kuantum teorisine yönelik memnuniyetsizliğin temelinde bu yatmaktadır. Bir örnek olarak, Schrödinger’in ünlü kedi örneğinin yakından incelenmesi fizikçilerin genellikle onun asıl amacını kaçırdığını göstermektedir. Felsefi bir eğilimin katkıda bulunabileceği şey, alternatif fizik değil, matematiksel bir biçimcilikten fiziksel bir resim çıkarmak için gerekli olan argümana gösterilen özendir.

Is time-travel possible? Like most intriguing problems that lie within the shared locus of physics, metaphysics and logic, this question admits of many interpretations, each of which engenders a different line of research. At its most anemic, the issue can be just: Is it possible to tell a story about travel into the past that contains no explicit contradictions? Under the stimulation of physical concerns it may develop into a more challenging problem: Do the laws of physics, as best we understand them, admit of solutions that contain closed time-like curves? And next: Would it be physically possible for a massive object to travel along one of those curves into its own local past? Then: Are the known facts about our universe consistent with it being such a world? And finally: Is time-travel in our universe technologically possible? When prodded in this direction our original question arrives at last on the drawing boards of the engineers, having passed successively through the precincts of the theoretical physicists, the mathematicians, and the astronomers.

Quantum mechanics predicts many surprising phenomena, including the two-slit interference of electrons. It has often been claimed that these phenomena cannot be understood in classical terms. But the meaning of “classical” is often not precisely specified. One might, for example, interpret it as “classical physics” or “classical logic” or “classical probability theory.” Quantum mechanics also suffers from a conceptual difficulty known as the measurement problem. Early in his career, Hilary Putnam believed that modifications of classical logic could both solve the measurement problem and account for the twoslit phenomena. Over 40 years later he had abandoned quantum logic in favor of the investigation of various theories - using classical logic and probability theory - that can accomplish these tasks. The trajectory from Putnam’s earlier views to his later views illustrates the difficulty trying to solve physical problems with alterations of logic or mathematics.

Translated here into Polish is Tim Maudlin’s “Distilling Metaphysics from Quantum Physics,” which is a chapter of The Oxford Handbook of Metaphysics. The author discusses six important metaphysical issues on which quantum physics sheds new light. He shows how differently each of the three main intepretations of quantum theory (von Neumann’s and GRW collapse theory, Bohm’s hidden variable theory, and Everett’s many-worlds theory) views each of them. The issues discussed are determinism, determinateness, the role of the observer, uncertainty and complementarity, quantum logic, and entanglement and non-locality.