What do you think?
Rate this book
Philosophy of Physics: Quantum Theory
A sophisticated and original introduction to the philosophy of quantum mechanics from one of the world's leading philosophers of physics
In this book, Tim Maudlin, one of the world's leading philosophers of physics, offers a sophisticated, original introduction to the philosophy of quantum mechanics. The briefest, clearest, and most refined account of his influential approach to the subject, the book will be invaluable to all students of philosophy and physics.
Quantum mechanics holds a unique place in the history of physics. It has produced the most accurate predictions of any scientific theory, but, more astonishing, there has never been any agreement about what the theory implies about physical reality. Maudlin argues that the very term "quantum theory" is a misnomer. A proper physical theory should clearly describe what is there and what it does--yet standard textbooks present quantum mechanics as a predictive recipe in search of a physical theory.
In contrast, Maudlin explores three proper theories that recover the quantum predictions: the indeterministic wavefunction collapse theory of Ghirardi, Rimini, and Weber; the deterministic particle theory of deBroglie and Bohm; and the conceptually challenging Many Worlds theory of Everett. Each offers a radically different proposal for the nature of physical reality, but Maudlin shows that none of them are what they are generally taken to be.
In this book, Tim Maudlin, one of the world's leading philosophers of physics, offers a sophisticated, original introduction to the philosophy of quantum mechanics. The briefest, clearest, and most refined account of his influential approach to the subject, the book will be invaluable to all students of philosophy and physics.
Quantum mechanics holds a unique place in the history of physics. It has produced the most accurate predictions of any scientific theory, but, more astonishing, there has never been any agreement about what the theory implies about physical reality. Maudlin argues that the very term "quantum theory" is a misnomer. A proper physical theory should clearly describe what is there and what it does--yet standard textbooks present quantum mechanics as a predictive recipe in search of a physical theory.
In contrast, Maudlin explores three proper theories that recover the quantum predictions: the indeterministic wavefunction collapse theory of Ghirardi, Rimini, and Weber; the deterministic particle theory of deBroglie and Bohm; and the conceptually challenging Many Worlds theory of Everett. Each offers a radically different proposal for the nature of physical reality, but Maudlin shows that none of them are what they are generally taken to be.
256 pages, Hardcover
Published March 19, 2019
100 people are currently reading
615 people want to read
Ratings & Reviews
Friends & Following
Create a free account to discover what your friends think of this book!
Community Reviews
Displaying 1 - 14 of 14 reviews
August 9, 2021
The Copenhagen interpretation of quantum mechanics has been notoriously hard to understand, Bohr even stated that there is no quantum world. As per the Copenhagen interpretation which a lot of physcists seem to have accepted as dogma, it makes no sense to even talk about the physical world outside of measurements. So questions like 'where was the electron before the measurement?' is simply absurd within the Copenhagen context. And this famously led to those jokes along the lines of 'does the moon exist when nobody is looking?'.
One of the first physicists to question the validity of this entire formulation (Besides Einstein, of course) was David Bohm. But Bohm achieved what other skeptics hadn't, he came up with an alternate mathematical formulation that was equivalent to the Schrodinger wave mechanics, but it dealt very elegantly with the measurement problem and that very important question: what are the limits of the quantum laws? Where do they stop being pertinent? What Bohm originally called the pilot-wave theory (although it was De Broglie who first proposed it, but he didn't work on it further because he was discouraged by his inability to answer the questions posed by Pauli, Heisenberg and Bohr during one of those Solvay conferences - oh you know it, that black and white picture with those famous European male physicists and Marie Curie? Yep, that one) is now the broader Bohmian mechanics and much of this book deals with that.
This book also explains bits of Bell's local beables theory, and the GRW collapse theory although not as extensively. It completely ignores the Copenhagen interpretation though, except for discussing its shortcomings.
Physicists and philosophers seem to be slowly growing disenchanted with the Copenhagen interpretation, which makes sense in 2021 given that the quantum mechanics that we study in universities sometimes completely disregards cause-and-effect, and locality. Even if Bell's theorem and experimental results proved that quantum mechanics is inherently non-local, with the rise alternative theories, the Copenhagen interpretation has been harder to accept for the simple reason that it does not provide a consistent description of reality. I myself seem to be straying away from it even though it's all I've been taught. Might even be 'just a phase', we'll see. But for now, I have to giggle at and agree with this quote from my favorite physicist John Stewart Bell:
Was the world wavefunction waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some more highly qualified measurer—with a Ph.D.?
One of the first physicists to question the validity of this entire formulation (Besides Einstein, of course) was David Bohm. But Bohm achieved what other skeptics hadn't, he came up with an alternate mathematical formulation that was equivalent to the Schrodinger wave mechanics, but it dealt very elegantly with the measurement problem and that very important question: what are the limits of the quantum laws? Where do they stop being pertinent? What Bohm originally called the pilot-wave theory (although it was De Broglie who first proposed it, but he didn't work on it further because he was discouraged by his inability to answer the questions posed by Pauli, Heisenberg and Bohr during one of those Solvay conferences - oh you know it, that black and white picture with those famous European male physicists and Marie Curie? Yep, that one) is now the broader Bohmian mechanics and much of this book deals with that.
This book also explains bits of Bell's local beables theory, and the GRW collapse theory although not as extensively. It completely ignores the Copenhagen interpretation though, except for discussing its shortcomings.
Physicists and philosophers seem to be slowly growing disenchanted with the Copenhagen interpretation, which makes sense in 2021 given that the quantum mechanics that we study in universities sometimes completely disregards cause-and-effect, and locality. Even if Bell's theorem and experimental results proved that quantum mechanics is inherently non-local, with the rise alternative theories, the Copenhagen interpretation has been harder to accept for the simple reason that it does not provide a consistent description of reality. I myself seem to be straying away from it even though it's all I've been taught. Might even be 'just a phase', we'll see. But for now, I have to giggle at and agree with this quote from my favorite physicist John Stewart Bell:
Was the world wavefunction waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some more highly qualified measurer—with a Ph.D.?
July 24, 2025
getricked in filosofie te lezen door de meest jobless guy van de Oude luikerbaan
October 4, 2021
Professor Maudlin is one of the leading philosophers of physics and his book on Quantum Theory is exceptionally good. He offers the most clear approach to a very difficult subject - the physical meaning of a quantum theory. Maudlin argues that the word "theory" is not even adequate in some cases since a true "theory" should provide an ontology (what there is) and a consistent set of equations for the dynamics (what it does, or how the ontology will evolve in time) and some interpretations of the quantum theory (like the famous "Copenhagen Interpretation") don't care to explain what is really happening - they just use well know rules (dubbed as "the quantum recipe" by Maudlin) to (successfully) obtain results and adopt the "shut up and calculate" attitude.
On the other hand, there are other approaches which Maudlin consider as "legitimate theories" in the sense of providing an ontology and the equations for it's evolution (dynamics). In particular, Maudlin gives a very well written account of three quantum theories: The GRW (Ghirardi-Rimini-Weber) spontaneous collapse theory, where the collapse of the wavefuncion is indeterministic, the Pilot Wave Theory (David Bohm), and the (very strange but mathematically consistent) Many World's interpretation (by Hugh Everett).
Each of these three candidates are "proper quantum theories" by Maudlin's account of what a legitimate physical theory should be, yet each one of them offers a very different view for the nature of physical reality. Nevertheless, all these theories are nonrelativistic, meaning they are based on a classic view of space and time which an absolute notion of simultaneity. The Theory of Relativity must be somehow taken into account in the search of a more realistic quantum theory. One theory of this kind is the very beautiful (and also mathematically challenging) Relativistic Quantum Field Theory (QFT), which Maudlin address in Chapter 7. In QFT, "elementary particles" are not fundamental entities, they emerge as excitations of quantum fields. Unfortunately even the powerful QFT approach cannot be still a complete account of reality since gravity is still left aside. In the quantum gravity approach to this problem (as proposed by Carlo Rovelli, Lee Smolin and others) spacetime should also treated as a quantum field, so the entire world would be made by just one single ingredient: covariant quantum fields.
Philosophy of Physics: Quantum Theory
On the other hand, there are other approaches which Maudlin consider as "legitimate theories" in the sense of providing an ontology and the equations for it's evolution (dynamics). In particular, Maudlin gives a very well written account of three quantum theories: The GRW (Ghirardi-Rimini-Weber) spontaneous collapse theory, where the collapse of the wavefuncion is indeterministic, the Pilot Wave Theory (David Bohm), and the (very strange but mathematically consistent) Many World's interpretation (by Hugh Everett).
Each of these three candidates are "proper quantum theories" by Maudlin's account of what a legitimate physical theory should be, yet each one of them offers a very different view for the nature of physical reality. Nevertheless, all these theories are nonrelativistic, meaning they are based on a classic view of space and time which an absolute notion of simultaneity. The Theory of Relativity must be somehow taken into account in the search of a more realistic quantum theory. One theory of this kind is the very beautiful (and also mathematically challenging) Relativistic Quantum Field Theory (QFT), which Maudlin address in Chapter 7. In QFT, "elementary particles" are not fundamental entities, they emerge as excitations of quantum fields. Unfortunately even the powerful QFT approach cannot be still a complete account of reality since gravity is still left aside. In the quantum gravity approach to this problem (as proposed by Carlo Rovelli, Lee Smolin and others) spacetime should also treated as a quantum field, so the entire world would be made by just one single ingredient: covariant quantum fields.
Philosophy of Physics: Quantum Theory
April 29, 2019
I give this book one star because it fails to cover and it admits in its introduction that it intentionally fails to cover the instrumentalist interpretation, commonly known as the "Copenhagen Interpretation", of physics which is the interpretation of it given by many of the founders of quantum theory (this book does not get into general relativity theory and its problems) and the only one that explains the evolution of science including physics into its present state and technique as data science. Thus it continues the present modern need of all philosophy both analytic and continental to turn philosophy into religion (for the latter they seem do so to justify social engineering, the former analytic school seems only to need secular religion to give meaning to their lives and academic tenure for their careers, otherwise they seem to accept the dogma of the continental school ). It rationalizes its exclusion of instrumentalist interpretation because it dogmatically states that a physical theory must answer the question: "what there is and what it does" or give "ontology" and "dynamics". In the present world in which even for physics, data science and correlation without explanation are taking over all theory including physics, for a supposed philosopher of physics to demand an "ontology" from a science is outright delusion. Ontology is a branch of philosophy not science. This book is not written as an ontology book, it assumes that ontology must come from physics which is not a philosophy of physics but a physics of philosophy. It is one thing to argue that ontology must be naturalized to science; it is another to assume that science must have an ontology for you or to satisfy your need for one. If you want to read and have some understanding of what are essentially metaphysical theories that hide as physical theories such as the logicians', mystics', and science fiction writers' beloved "Many World" theory, this book deserves 5 stars. Otherwise, if you want a real understanding or philosophy of physics as it is and not as it should be in order to satisfy a religious need for physics to explain life for you, I suggest you go old school and read something by the late Norwood Russell Hanson.
December 27, 2022
Definitely one of the best introductions to and clarifications of the issues that riddle the current understanding of quantum mechanics written so far. Concise, to the point, and exposed systematically, from the introduction of 8 emblematic experiments to the presentation of the "quantum recipe", and finally the description of a selection of attempts to make sense of the recipe with proper theories (collapse theories, pilot wave, many worlds). Maudlin does not abide to the historical order and rather puts the developments in logical order, presenting the formalism first and not shying away from admitting that quantum mechanics as typically taught is just an operational recipe, if of unprecedented success in accounting for experimental data. It cannot be ranked as a theory, given that its components (assigning a wavefunction to the system under study, evolution of the wavefunction in time, assignment of probabilities to the predictions extracted from the "measurement") are in themselves not rigorously justified, nor linked to an ontology. Maudlin is then particularly in the look out for a local ontology for a theory, following on the steps of John Bell and his "local beables", therefore he does not dwell on quantum bayesianism and other observer-centered theories. Maudlin also shortly discusses the extension of the non-relativistic versions of the theories to the relativistic domain, where instantaneity is not given and the number of particles is not fixed. Collapse theories are those closer to the recipe though admittedly phenomenologic in spirit; pilot wave theories add particles to the ontology, but suffer in the extension to relativistic theory due to the use of absolute simultaneity; and many worlds remain plagued with the transition from wavefunction to beables in spite of being easily extended to a relativistic version given that they do not contemplate a wavefunction collapse.
The author does not open new ground nor seem to be suggesting a preferential development in any single direction (though he evidences shortcomings particularly in many worlds), rather polishes and cleans up the discussion on the ontology of the theory and stimulates further work. A concluding chapter with a summary and explicit comparison among the theories would have made the book even stronger.
The author does not open new ground nor seem to be suggesting a preferential development in any single direction (though he evidences shortcomings particularly in many worlds), rather polishes and cleans up the discussion on the ontology of the theory and stimulates further work. A concluding chapter with a summary and explicit comparison among the theories would have made the book even stronger.
September 13, 2023
It's a good book, but barely touches on any philosophy of science. We're told from the start to dismiss antirealist construals of quantum physics without any argument, and that we should desire from a physical theory a realist ontology and dynamics. But this seems backwards - we hope that there's an ontology and dynamics for quantum theory because we've been successful at designing ontologies and dynamics for theories at higher levels; but if we're committed to reductionism, e.g. that the contents of our higher level theories are emergent and that the "real stuff" they're made out of exists only at the fundamental quantum level, then our desires are completely misaligned. We have no reason to expect that the nonreferring, idealized, and approximated descriptions of our higher level theories correspond to fundamental reality.
This book also doesn't really motivate how we would settle Many Worlds vs Bohmian Mechanics vs Objective Collapse models. The empirical equivalency of these theories is overlooked, and no appeal to theoretical virtues is even attempted, which is odd because realist physical theories appeal to theoretical virtues and inference to the best explanation all the time. You're left wondering "Who cares?" and edging closer to siding with the shut-up-and-calculate physicists as the book fails to deliver any decisive answers, or even sketch out how one of these theories would be falsified. The only constraint the author enforces is that the interpretations recover the quantum recipe. Some paragraphs are wasted explaining high level mathematics that could instead be spent on situating this work in a historical or philosophical or pragmatic context.
Overall, the book is mostly devoid of philosophy. If you're interested in learning about QM intepretations, this book will definitely be an aid, but if you're interested in thinking critically about what we're doing in quantum theory, then it isn't too helpful, and ironically parrots the same shut-up-and-calculate attitude except towards pursuing seemingly unsettleable metaphysical questions.
This book also doesn't really motivate how we would settle Many Worlds vs Bohmian Mechanics vs Objective Collapse models. The empirical equivalency of these theories is overlooked, and no appeal to theoretical virtues is even attempted, which is odd because realist physical theories appeal to theoretical virtues and inference to the best explanation all the time. You're left wondering "Who cares?" and edging closer to siding with the shut-up-and-calculate physicists as the book fails to deliver any decisive answers, or even sketch out how one of these theories would be falsified. The only constraint the author enforces is that the interpretations recover the quantum recipe. Some paragraphs are wasted explaining high level mathematics that could instead be spent on situating this work in a historical or philosophical or pragmatic context.
Overall, the book is mostly devoid of philosophy. If you're interested in learning about QM intepretations, this book will definitely be an aid, but if you're interested in thinking critically about what we're doing in quantum theory, then it isn't too helpful, and ironically parrots the same shut-up-and-calculate attitude except towards pursuing seemingly unsettleable metaphysical questions.
May 21, 2019
This is a remarkable book. The author is focussing on physical theories of what he calls the "quantum recipe" (ie the mathematical and predictive elements of quantum mechanics). As such, he does not consider theories that are not physically possible, ie the Copenhagen interpretation. Rather he considers 3 nonrelativistic theories and briefly touches on quantum field theory. His main concerns are: what are the fundamental ontologies of these theories? how do they relate to the wavefunction/quantum state? how do they relate to violations of Bell's inequality? and how do they account for the relationship between macroscopic objects and microscopic particles?
One concern I have is with the easy dismissal of categorization (per Aristotle's categories) for the quantum state. The author states that this is not at all necessary for something as unique and mind boggling as the quantum state; rather, we should consider it ontologically basic. I found this justification odd and I am not convinced by it.
Although it is an introduction, it definitely has to be read very very carefully. A book worth revisiting, if only for how the author presents the 8 basic experiments of quantum physics.
The author apologetically acknowledges that relativistic theories are important, but justifiably believes that the main concerns of physical theories of quantum mechanics can, for pedagogical purposes, be better approached through the nonrelativistic theories presented. I am inclined to agree with him.
Note that there are many many resources on the Copenhagen interpretation out there, so it's nice to read a work that doesn't focus on it (for once). Also this isn't a work of the history of science; you're better off reading that elsewhere (eg Cushing).
One concern I have is with the easy dismissal of categorization (per Aristotle's categories) for the quantum state. The author states that this is not at all necessary for something as unique and mind boggling as the quantum state; rather, we should consider it ontologically basic. I found this justification odd and I am not convinced by it.
Although it is an introduction, it definitely has to be read very very carefully. A book worth revisiting, if only for how the author presents the 8 basic experiments of quantum physics.
The author apologetically acknowledges that relativistic theories are important, but justifiably believes that the main concerns of physical theories of quantum mechanics can, for pedagogical purposes, be better approached through the nonrelativistic theories presented. I am inclined to agree with him.
Note that there are many many resources on the Copenhagen interpretation out there, so it's nice to read a work that doesn't focus on it (for once). Also this isn't a work of the history of science; you're better off reading that elsewhere (eg Cushing).
June 22, 2024
Let me share my thoughts on Tim Maudlin's book on quantum theory—a work that truly stands out in its ability to unravel the complexities of quantum physics with clarity and depth.
Maudlin navigates through the enigmatic realm of quantum theory with an adeptness that makes even the most intricate concepts comprehensible. Whether discussing the dual nature of particles, the phenomenon of entanglement, or the philosophical implications of quantum mechanics, he strikes a balance between scholarly rigor and engaging narrative.
What distinguishes Maudlin's approach is his willingness to delve into not only the scientific intricacies but also the profound questions that arise from them. He deftly explores the implications of quantum theory for our understanding of reality and consciousness, offering readers a thought-provoking journey into the fundamental nature of existence.
The prose is elegantly crafted, making complex ideas accessible without compromising on depth. It feels as though one is engaged in a stimulating conversation with a knowledgeable companion, where every explanation is meticulously thought out yet presented with a conversational ease.
For anyone seeking a comprehensive exploration of quantum theory that is both intellectually stimulating and accessible, Tim Maudlin's book is an indispensable read. It not only clarifies the mysteries of quantum mechanics but also invites readers to contemplate the profound implications of these discoveries on our perception of the universe.
Maudlin navigates through the enigmatic realm of quantum theory with an adeptness that makes even the most intricate concepts comprehensible. Whether discussing the dual nature of particles, the phenomenon of entanglement, or the philosophical implications of quantum mechanics, he strikes a balance between scholarly rigor and engaging narrative.
What distinguishes Maudlin's approach is his willingness to delve into not only the scientific intricacies but also the profound questions that arise from them. He deftly explores the implications of quantum theory for our understanding of reality and consciousness, offering readers a thought-provoking journey into the fundamental nature of existence.
The prose is elegantly crafted, making complex ideas accessible without compromising on depth. It feels as though one is engaged in a stimulating conversation with a knowledgeable companion, where every explanation is meticulously thought out yet presented with a conversational ease.
For anyone seeking a comprehensive exploration of quantum theory that is both intellectually stimulating and accessible, Tim Maudlin's book is an indispensable read. It not only clarifies the mysteries of quantum mechanics but also invites readers to contemplate the profound implications of these discoveries on our perception of the universe.
April 2, 2022
captivating
It is refreshing to see someone dismiss in a few words the So called Copenhagen Interpretation as something not even worth discussing. And to take physicists to task for their frequent naive misuse of well established terms such as … well ‘realism’.
The author then outlines the methods of (non relativistic ) quantum mechanics - the quantum recipe as he calls it - and then asks for real physical theories that would provide some account of the recipe and its success.
Pilot waves, many worlds etc.
There are some technical details but not really enough if you don’t already know them. A common problem with books of this type.
There are some good references to more advanced works.
He dismisses statistical and epistemic theories and advocates openly for ontological ones. There is no nonsense about conscious observers and not even a heavy emphasis on ‘measurement’ as such.
We are left asking, ‘so what is the quantum state of an object or system, and how can it be so implicitly non-local’ and how can it behave the way it does.
It is refreshing to see someone dismiss in a few words the So called Copenhagen Interpretation as something not even worth discussing. And to take physicists to task for their frequent naive misuse of well established terms such as … well ‘realism’.
The author then outlines the methods of (non relativistic ) quantum mechanics - the quantum recipe as he calls it - and then asks for real physical theories that would provide some account of the recipe and its success.
Pilot waves, many worlds etc.
There are some technical details but not really enough if you don’t already know them. A common problem with books of this type.
There are some good references to more advanced works.
He dismisses statistical and epistemic theories and advocates openly for ontological ones. There is no nonsense about conscious observers and not even a heavy emphasis on ‘measurement’ as such.
We are left asking, ‘so what is the quantum state of an object or system, and how can it be so implicitly non-local’ and how can it behave the way it does.
July 11, 2025
A very interesting (though highly introductory) book, which seems to be completely free of common misconceptions and presents its subject matter in an exceptionally clear and rigorous manner. (Of course that is a thoroughly stereotypical thing to write, but it's also true.) That being said there is one very irritating thing about it. Maudlin ends book 1 in the series, on space & time, with some very interesting considerations of the arrow of time, but he leaves them unresolved on the grounds that answering those questions would require quantum mechanics; I believe the last sentence in the book is a promise to return to the subject in the next book. But he has apparently completely forgotten that promise; not only does he fail to discuss the topic, he doesn't even apologize for leaving it out.
April 15, 2021
Quite an interesting book on the ontological and interpretational aspects of Quantum Mechanics. It mainly tackles three 'schools' of Interpretations : Collapse Theories (GRW, Local Beables etc), Pilot Wave Theory and the Many World Theory. The author(s) have done quite a good job of explaining how each of these interpretations can be equipped with an individual ontological foundation that connect the bras and the kets to physical, tangible entities and phenomena. A possible ontology for Quantum Field Theory is discussed in the last chapter.
January 28, 2022
One of the best introduction to your humanities friends about why quantum mechanics is "weird" or unintuitive. The actual interpretations falls off quite a bit and Maudlin fails to really articulate why they're so unsatisfactory. Relativity chapter is also lacking, but pretty insightful for an analysis without any math
July 23, 2025
Not for your average Joe
I had hoped this book would help me better understand quantum mechanics, but it left me more confused than before. It’s clearly written for students of the subject, not for general readers.
I had hoped this book would help me better understand quantum mechanics, but it left me more confused than before. It’s clearly written for students of the subject, not for general readers.
Want to read
December 27, 2023Anbefalt av Einar og Viro
Displaying 1 - 14 of 14 reviews