What do you think?
Rate this book
Duch w atomie. Dyskusja o paradoksach teorii kwantowej
Redaktorzy radia BBC przeprowadzili wywiad z ośmioma wybitnymi fizykami: Alainem Aspectem (od doświadczeń z fotonami), Johnem Bellem (autorem nierówności Bella), Johnem Wheelerem (promotorem Feynmana), Rudolfem Peierlsem (od przejścia Peierlsa metal/półprzewodnik). Johnem Taylorem, Davidem Bohmem (autorem koncepcji deterministycznej parametrów ukrytych) i Basilem Hileyem. Zadziwia to, że wszyscy ci fizycy mają "bardzo" różniące się poglądy na interpretacje mechaniki kwantowej. Szczególnie cenny w książce jest rozdział I, podsumowujący problemy interpretacyjne.
179 pages, Hardcover
First published January 1, 1986
30 people are currently reading
909 people want to read
About the author
Paul C.W. Davies
75 books572 followersPaul Charles William Davies AM is a British-born physicist, writer and broadcaster, currently a professor at Arizona State University as well as the Director of BEYOND: Center for Fundamental Concepts in Science. He has held previous academic appointments at the University of Cambridge, University of London, University of Newcastle upon Tyne, University of Adelaide and Macquarie University. His research interests are in the fields of cosmology, quantum field theory, and astrobiology. He has proposed that a one-way trip to Mars could be a viable option.
In 2005, he took up the chair of the SETI: Post-Detection Science and Technology Taskgroup of the International Academy of Astronautics.
In 2005, he took up the chair of the SETI: Post-Detection Science and Technology Taskgroup of the International Academy of Astronautics.
Ratings & Reviews
Friends & Following
Create a free account to discover what your friends think of this book!
Community Reviews
Displaying 1 - 24 of 24 reviews
May 16, 2018
Quantum mechanics is not simple. I actually read this book two times, and still don't have a solid grasp of the details underpinning the Aspect experiment, much less the mathematics, why it works so well, and what it all means. But that's not the point of this book. The main point (to me) is showing a broad audience the controversies surrounding interpretation of quantum mechanics.
Since quantum mechanics is one of the most successful scientific theories ever, in terms of predicting results of experiments, and the discipline of physics is interested in understanding precisely how the world works, it is natural to want to interpret the physical meaning underlying quantum mechanics. But the interpretation is not simple, and even mis-aligns with classic physicists.
This book has two parts:
1. Explain quantum mechanics as simply as possible (Chapter 1),
2. Interviews with leading physicists who advocate certain interpretations (Chapters 2-9)
The main interpretations are Copenhagen, Many Universes, Ensemble, Quantum Field Theory, and Quantum Potential. Naturally, all physicists interviewed believe their position is correct.
The Copenhagen interpretation seemed the most prominent, and is a little eery. From what I gather, it is inextricably linked with the Heisenberg Uncertainty principle, which states we can't measure both the position and velocity of an electron simultaneously. The eeriness comes from the implication that things don't exist until they are observed, which interesting relates to the old saying: "If a tree falls in a forest and no one is there, does it make a sound"? Supporters of objective reality "out-there" (Einstein) believe that of course the tree makes a sounds, but some (e.g. Eugene Wigner) may claim that no sound is made unless a conscious observer hears it.
As a statistician, it is interesting to see physicists interpreting probabilities, especially when their careers are at stake, and they're discussing one of the most fundamental problems in science. Statisticians can glean subtle but interesting insights here. For example, David Deustch was asked "why do we need an interpretation", and he gave the very interesting two part answer:
1. The whole point of physics is explaining reality
2. If we just say they're algorithms, who cares, then we may halt scientific progress.
I wonder if these relate to statistics, whose famous motto can be summarized as "All models are wrong, but some are useful". Clearly, statisticians don't care as much about their models matching objective reality, and are more than happy to use them for pragmatic purposes.
**Caution** This book is relatively old, so I should look into more recent takes on Quantum Mechanics to see if anything has been resolved since.
Since quantum mechanics is one of the most successful scientific theories ever, in terms of predicting results of experiments, and the discipline of physics is interested in understanding precisely how the world works, it is natural to want to interpret the physical meaning underlying quantum mechanics. But the interpretation is not simple, and even mis-aligns with classic physicists.
This book has two parts:
1. Explain quantum mechanics as simply as possible (Chapter 1),
2. Interviews with leading physicists who advocate certain interpretations (Chapters 2-9)
The main interpretations are Copenhagen, Many Universes, Ensemble, Quantum Field Theory, and Quantum Potential. Naturally, all physicists interviewed believe their position is correct.
The Copenhagen interpretation seemed the most prominent, and is a little eery. From what I gather, it is inextricably linked with the Heisenberg Uncertainty principle, which states we can't measure both the position and velocity of an electron simultaneously. The eeriness comes from the implication that things don't exist until they are observed, which interesting relates to the old saying: "If a tree falls in a forest and no one is there, does it make a sound"? Supporters of objective reality "out-there" (Einstein) believe that of course the tree makes a sounds, but some (e.g. Eugene Wigner) may claim that no sound is made unless a conscious observer hears it.
As a statistician, it is interesting to see physicists interpreting probabilities, especially when their careers are at stake, and they're discussing one of the most fundamental problems in science. Statisticians can glean subtle but interesting insights here. For example, David Deustch was asked "why do we need an interpretation", and he gave the very interesting two part answer:
1. The whole point of physics is explaining reality
2. If we just say they're algorithms, who cares, then we may halt scientific progress.
I wonder if these relate to statistics, whose famous motto can be summarized as "All models are wrong, but some are useful". Clearly, statisticians don't care as much about their models matching objective reality, and are more than happy to use them for pragmatic purposes.
**Caution** This book is relatively old, so I should look into more recent takes on Quantum Mechanics to see if anything has been resolved since.
April 11, 2020
This book talks about the mysteries of quantum mechanics. It emphasizes especially on the world view that the quantum mechanics brought to us. The book gives several examples of the philosophical explanation of the weirdnesses of quantum mechanics.
The good part of the book is that it includes several interviews with famous physicists who worked within quantum mechanics and talked about their important works related to it. This is actually the major part of the book and it gives the reader a great insight to the topic from the most worthy people.
The bad part of the book is that it is not easy to understand both due to the complexity of the topic and due to the oversimplified language. The book is full of arguments that do not get explaned properly. Most of them are considered as "it is easy to see" but they are not even for an engineering physics student like me.
Overall, I recommand this book if you are interested in the philosophical problem rised by the quantum mechanics or want to hear from some of the greatest quantum mechanics physicists in our time.
The good part of the book is that it includes several interviews with famous physicists who worked within quantum mechanics and talked about their important works related to it. This is actually the major part of the book and it gives the reader a great insight to the topic from the most worthy people.
The bad part of the book is that it is not easy to understand both due to the complexity of the topic and due to the oversimplified language. The book is full of arguments that do not get explaned properly. Most of them are considered as "it is easy to see" but they are not even for an engineering physics student like me.
Overall, I recommand this book if you are interested in the philosophical problem rised by the quantum mechanics or want to hear from some of the greatest quantum mechanics physicists in our time.
September 15, 2014
Conjunto de entrevistas realizadas por los autores a los científicos punteros en mecánica cuántica. Una a una se nos van presentando las distintas interpretaciones de la teoría, siempre apoyadas por las opiniones de los que la denfienden. En conjunto dan una idea clarificadora sobre la teoría más controvertida de la física. Buen libro, aunque un tanto difícil de entender por momentos. [Nota, comenté este libro hace 19 años y transcribo ese comentario, con el que ahora mismo no estoy de acuerdo: la teoría cuántica NO es controvertida, y no lo ha sido dese que Einstein fracasó en su paradoja EPR y las variables ocultas se descartaron].
March 26, 2019
โลกควอนตัมซับซ้อน ลึกลับ ไม่แน่นอน เหมือนจริง แต่บางมุมมองก็เหมือนผี เล่มนี้สนุกตรงนักฟิสิกส์แต่ละคนก็มีความเชื่อแตกต่างกัน หลายบทเราตามไม่ทันนะ มาวิชาการจ๋า ก็แบลงก์ไปเลย ถึงอย่างนั้นมันก็ยังน่าสนใจอยู่ดี การพยายามพิสูจน์ความเป็นไปได้ของพหุภพ การส่งสัญญาณกลับไปอดีต ค้นหาและครุ่นคิดด้วยวิธีการทางวิทยาศาสตร์และหลักปรัชญา ที่จะพาเราไปไกลยิ่ง ๆ ขึ้นกว่านี้
April 23, 2015
Even if this book is designed for no-physicists. I'm not sure how easy it is to follow.
It is composed of interviews of various physicists: theoretical physicists, experimental physicists in different field related to quantum mechanics who answer questions about the interpretation of quantum theory.
The first side is to say that the mind of the observed has an impact on the world around and that the observer is outside of the system. An idea that for me doesn't seem to hold with quantum cosmology when extended to the entire universe and therefor placing the mind of the observer outside of the universe.
On the other side there is the many universes theory allowing an infinite number of parallel universes. In this case having a infinite number of universe seem to be a problem as most believe those other universe can't be reached, which other believe they are reached through interference patterns at an atomic level.
It was a fun read and totally redefines what you consider as "reality".
It is composed of interviews of various physicists: theoretical physicists, experimental physicists in different field related to quantum mechanics who answer questions about the interpretation of quantum theory.
The first side is to say that the mind of the observed has an impact on the world around and that the observer is outside of the system. An idea that for me doesn't seem to hold with quantum cosmology when extended to the entire universe and therefor placing the mind of the observer outside of the universe.
On the other side there is the many universes theory allowing an infinite number of parallel universes. In this case having a infinite number of universe seem to be a problem as most believe those other universe can't be reached, which other believe they are reached through interference patterns at an atomic level.
It was a fun read and totally redefines what you consider as "reality".
October 7, 2019
This book starts by enlightening the reader on the profound implications of quantum mechanical predictions and experimental results: particularly in regard to the experiments undertaken by Alain Aspect, who is the subject of an interview which later features. Elementary wave mechanics and intriguing thought experiments are fastidiously described, and supply a suitable groundwork from which to understand the fascinating takes the leaders in the field of QM have. Interpretations from the Copenhagen, and Everett to statistical and non-local hidden variable theories are explained and defended by some of their main proponents.
Anyone interested in philosophical meaning of QM, or who are curious about the promise of other possible alternatives to the main Copenhagen interpretation should consider reading this book.
Anyone interested in philosophical meaning of QM, or who are curious about the promise of other possible alternatives to the main Copenhagen interpretation should consider reading this book.
December 13, 2010
Great coverage of the measurement problem, Copenhagen interpretation and other alternative views. The book is a bunch of conversations with leading physicists of 1980s.
February 3, 2017
This little book is a gem. I read it in one sitting. To read the opinions of the actual physicist about their own take on quantum mechanics and relativity was quite interesting.
July 30, 2016
1) In two slit experiment, particles make an interference pattern, which means they act like waves. This also means that each particle goes through both slits. However, if you close one of the slits or put detectors on slits, particles don't make an interference pattern, which means they act like waves, and each particle goes one slit or another NOT BOTH. Then, how they "know" if there is a detector or one of slits are closed? One of answering this question is that particles don't have well-defined paths. They go through every possible ways.
2) An experiment was pointed out by John Wheeler is Delayed Choice Experiment, which shows that we can determine the path of particles AFTER each particle has already traversed. It seems like observation can affect past of the particles. This experiment was implemented:
http://images.iop.org/objects/phw/new...
In this image, mirrors divides each particle. If we put half-silvered mirror(which means it only reflects not propagate) on BS2, we can know which way particle has taken and we won't see interference pattern. However, if we don't put a half-silvered mirror, we can't know which way particle has taken and therefore we will see interference pattern on both detectors.
Copenhagen Interpretation
According to Bohr, it is meaningless to ask "what is electron" when we don't observe it. Either we can leave electrons alone and observe an interference pattern, or we can take a peek particles' trajectories and wash out the pattern. Two situations are not contradictory but complementary such as momentum-position complementary. Therefore, Copenhagen Interpretation says it is meaningless to say electron exists on its own(not as a result of an observation).
If an atom is excited at t1, then quantum mechanics can calculate the probability of that it will no longer be excited at t2. All we know the observations of its energy at t1 and t2. We don't need to assume anything between t1 and t2. For example, energy is not an abstract thing but conserved mathematical analogy that observations of mechanical process. What Bohr suggests things like electron, photon, atom... is the same.
This traditional interpretation creates a paradox in it because it gives very importance to observer. Geiger counter, which is an apparatus used to observe, is also made of quantum objects. Troubles arise when we ask where the dividing line comes between quantum(microscopic) and classic(macroscopic) world. Particles don't posses well-defined properties. However, they do after we make a measurement and we can choose which measurements to make, either position or momentum. If you put a particle in a state of given position, and then decide to measure the momentum, you get a particular value, although the value can't be predicted. The rules of quantum mechanics say, a quantum system can evolve in time in two quite distinct ways. When observation is made, waves that were used to interfere with each other have disappeared but one of them. We cannot undo it and restore the original complex wave pattern, which means mathematically "non-unitary". We can considered both apparatus and quantum object as an isolated system. Yet, this also leads into the paradox because we need another apparatus to determine the quantum state the former apparatus and so on. Von Neumann(and Eugene Wigner) concluded that consciousness can be an end to this vicious circle. However, this seems also paradoxical. For example, if we replace a person with the cat in Schrödinger's thought experiment and if the person is in a superposition state(dead and alive) when we open the box(let's say the person is alive) we can ask the person how he felt before we opened the box. Maybe because the person is a conscious, he collapse the wave function. Some say even the cat can be count as an conscious observer. "Drawing line" problem is now between conscious and unconscious.
Many-Universes Interpretation
When we consider the quantum cosmology unless mind is involved, we must think an external apparatus beyond our universe. Hugh Everett proposed a radical interpretation which, it is claimed, requires less assumption than the traditional interpretation. According to Everett, transition occurs because the universe slips into copies where each quantum states are real in each copies. Therefore, the number of copies depends on the number of quantum states. Furthermore, these universes are the same completely except the quantum state. For example, in Schrödinger's thought experiment in one of the universes cat would be alive whereas cat would be dead in the other. A proponent of this interpretation, Bryce DeWitt expressed it as: Every quantum transition taking place in every star, in every galaxy, in every remote corner of the universe is splitting our local world on Earth into myriads of copies of itself. Here is schizophrenia with vengeance. There two major criticism against it. One is that the interpretation has lots of excess metaphysical baggage while we observe only one universe. In defense, proponents say, the interpretation emerges formal rules of quantum mechanics, without making any epistemological hypothesis despite other interpretations. The other is that it is unstable. If our consciousness is confined to one universe at a time, how could we confirm or refute the others? David Deutsch say it can be tested by very intelligent computers in future. Some say this interpretation may also explain why the universe we living looks arranged precisely so that living creatures arise.
The statistical Interpretation
This interpretation abandons what actually goes on in an individual quantum object. Quantum mechanics seems working good statistically, however there is no case to answer as regards the measurement problems. Therefore, there is no way to know what actually happens when a particular measurement takes place.
Uncertainty, Non-locality and Bell's Theorem
Suppose a single stationary particles explodes into two particles. Uncertainty Principle forbids us from knowing position and momentum of either particle definitely at the same time. We choose one or the other to be well defined. However, because of conservation of momentum, we can measure the momentum of a particle to deduce the that of other one and also by symmetry one of particle must move a distance equal to that of the other one(also if particles are photons, their polarization must be the same).
If faster than light communication is false, quantum mechanics must be incomplete. Bell introduced some inequalities to test this idea. To illustrate, the number of black people can't be greater the number of men plus the number of women. If quantum mechanics is true, Bell inequalities must be exceeded(they were in Aspect's experiment). Entanglement is incompatible with objective reality or locality. By objective reality, we mean the reality of the external world that is independent of our observations. By locality, we mean not instantaneous but separable effect. If one wants to accept entanglement, one should leave locality or objective reality.
John Bell: The Aspect experiment did not prove indeterminism of quantum world, it only proved action at a distance. It must certainly be explored that the hypothesis which says mind has an essential role in physics but it certainly has paradoxes in it. Pre-Einstein position of Lorentz and Poincare, Larmor and Fitzgerald is perfectly coherent and consistent with relativity theory. Thus, we should get back the idea of aether because if all Lorentz frames are equivalent, things can go back in time. Quantum theory is a temporary expedient. It's enough reason to dislike the many-universes interpretation that we only observe one universe. The de Broglie-Bohm theory was developed for non-relativistic quantum mechanics. If you try to extend it to the relativistic context, you will have difficulties.
John Wheeler: The complementarity description of Bohr was the only possible objective(rational) description. The many-universes interpretation seemed to represent the logical follow-up formalism of quantum theory. However, there's too much metaphysical baggage carried along with it. It also takes quantum theory as the currency and leaves the observation as a mere secondary phenomenon, the primary concept must be make meaning out of observation. Maybe philosophy is too important to be left to the philosophers. Consciousness has a crucial role. It seems we can influence on which path a photon will take. As Bohr said, we have no right to talk about what photon is doing until we observe it and also the pas has no meaning or existence until it exist as a record, this can be view as we, conscious observers, are responsible for reality. The gravitational lens effect provides us to see what delayed-choice experiment do in cosmological level.
Rudolf Peierls: There is only one interpretation and one way to understand quantum mechanics - Copenhagen Interpretation. Therefore, when you refer to Copenhagen Interpretation, what you really mean is quantum mechanics. Table(a macroscopic object) is not real until we observe it. We can't replace observer with inanimate device. Suppose you have an apparatus that tells you whether a radioactive atom decayed or not by the position of a pointer. To determine the position of the pointer, you need to shine light on it. Bu you only know the possibility of light being reflected. It goes until you become conscious of that experiment has one result. If you put an unconscious observer such as camera, wave packet won't collapse. Universe wasn't unreal(undecided) before us because we have the information of 13 billion years ago. There is no sensible view of hidden variables theory that doesn't conflict with Aspect Experiment. If we don't communicate with other universes, why invent them?
David Deutsch: The Many-Universes Interpretation is that there are parallel universes which include all existing at the same time and normally not communication with each other. However, they have some influence on each other in microscopic level, that's the reason why we postulate them. It is the simplest interpretation of quantum theory because it involves the fewest assumptions in it. That human consciousness has direct effect on the nature is more unacceptable than the parallel universes. The exact number of universes depends on physical theories which we don't know yet but it's safety to think it's very large, probably infinite. In his favorite way of looking, there is an infinite number of universes and this number does not change but content does. Before choice is made, all the universes are identical; when choice is made, they partition themselves into two groups. Everett proposed universe is branching itself, the reason was that if there was a collection of identical universes, he preferred to speak of it as being one universe. The problem of arrow of time is not also solved in this interpretation. The coming together of universes on a small scale can occur, interference experiment provides an indirect evidence of the fusion of two groups universe into one. The way that Everett interprets Double-Slit Experiment is to say there were two groups of universes that in one universe the photon passed through one slit, and in the other the photon passed through the other slit, but later appeared in the same position, which means that the universes were the same again. Physical reality is the set of all universes evolving together, you cannot move one without moving the others. So parallel universes are connected as the universes of past and future. Copenhagen Interpretation fails in quantum cosmology. It's logically inconsistent to imagine observer outside of the universe. Another advantage of the interpretation is that it will work before we know what an observer is, contrary to the other interpretations.
Suppose an artificial observer(such as computer) which observes an interference phenomenon inside his mind. He tries to observe the effect of different internal states of his brain in different universes interacting with each other. These internal states are set up by a special organ which is essentially another quantum memory unit. The observer's mind differentiate itself into two universes. At the intermediate stage, he will write down "I'm here observing one of the two states". Moreover, he will write down the same thing in both universes because he won't tell which of the two states he observes and won't remember. If interference occurs it means Everett's interpretation is true; however, it does not it means conventional interpretation is true, which says all universes but only one will have disappeared.
John Taylor: the ensemble(statistical) interpretation says when we're observing a quantum system what we're actually doing is that we're making a measurement on an aggregate or ensemble of identically system. Hence, our results takes the form of a probability distribution of particular values for that measurement. We're not allowed to describe what is going on for an individual system. For example, in quantum entanglement we can't talk about the spin of an individual particle, we can only say some ensembles(nearby particles) has spin up/down while the other ensembles(far away particles) has opposite. There is a distinction between measuring and preparing. If you're preparing a state of an ensemble, then you know it will have properties identical with that preparation in the future. If you make a measurement, then you will have been able to gather what it was like before the measurement in the past. We can measure an individual electron, however, there will be an infinite range of possibilities. If we take an individual case in Schrödinger's experiment, it's meaningless to ask whether the cat is alive or dead. We can have wave function to describe the whole universe.
David Bohm: The Copenhagen interpretation only gives a formula describing the probability of what can be observed in a piece of apparatus. Yet the apparatus itself is made of atoms, therefore you should use another piece of apparatus to look at it. Every physicist believe that the external world exists. Descartes said that though is enfolded and matter is extended. However, both are enfolded and both unfold, therefore they are similar in their basic structure. Something can unfold either as a wave-like or a particle-like.It's very similar to the mathematics of the hologram. Think a tree grew from a seed. You can't say the tree was in the seed because its structure also depends on environment like matter does. Experiments and the questions we ask are determined by our way of thinking. In quantum theory we're now asking a certain kind of questions and we're getting a certain kind of answer. Faster that light signalling can make paradoxes such as being able to signal our own past. However, the present theories are not the last word and special relativity will be going to an approximation just as Newtonian mechanics. When we discovered new theories, we will get rid of all these paradoxes. Quantum mechanics does not explain anything but describe it. The quantum potential, which is carried as a wave, can affect particles even quiet far away from the slits, it's influence depends on the form not magnitude. For example, the quantum potential is different if second slit is open/close in double-slit experiment. It has never been introduced like tis new kind of wave(called "active information" by Bohm). We have no control over the influences that propagate faster than light therefore it doesn't violate the special relativity. This quantum potential field does not look like electromagnetic field because electromagnetic field is too simple. The Schrödinger's equations are sufficient to explain both the quantum potential and the many-body problem. Bohm doesn't accept physics is only about making models that explain observations. He doesn't accepet even Popper's idea, which say a theory can be regarded as scientific only if it's falsifiable.
Basil Hiley: "If anybody came to me and said 'I want to solve a certain physical problem, I would recommend that they go ahead with the conventional interpretation" he said, even though he was used to work with Bohm on non-local quantum potential. What we have to try and do is to build up a model which is intuitive and quantum mechanics seems completely counterintuitive. The model(quantum potential) was originated by de Broglie and subsequently developed by David Bohm. In this model, there is an actual particle that has both a definite momentum and a definite position and the wave function does not represent probability but a real field. The field can influence the behaviour of this or other particles, the motion can be derived by Schrödinger's equation. When an electron pass through slits, the result on the other side looks like as if two waves made an interference with each other. Contrary to orthodox theory, the wave is really an average of how a beam individual electron behave, and the intensity of the wave corresponds to the number of electrons arriving at that particular spot in a given time. Another contradiction with orthodox theory is that quantum potential enables you to calculate the set of individual trajectories that give rise the interference pattern. it seem quantum potential gives some information about environment to the particle. Therefore, one can regard the wave as a field of information more that a physical field. It's like direction of a ship's depending on what it receives information from environment by radar waves. Richard Feynman had already pre-empted (us) in saying that he thought of a point in space-time being like a computer with an input and output connecting neighbouring points. So the electron may act like a computer. The motive power that decides how particle act like, of course, comes from the quantum potential itself. The quantum potential does not violate special relativity because it offers an absolute in the background, the quantum aether. In quantum formalism state function for the cat at the end of experiment is a linear superposition of a cat alive and a cat dead. These two states exist together in some way. Hiley doesn't see why mind should be introduced into physics at this level, He's also not keen on the many-universes interpretation because we seem to be producing many universes of which only one is observed by us. Uncertainty that Heisenberg introduced is caused by the apparatus. The reason why there is Planck's constant in this uncertainty is that the constant is not relevant. It seems it is because if you put Planck's constant equal to zero, you will get classical mechanics from the quantum formalism. Moreover, the quantum potential contains Planck's constant, therefore if Planck's constant changed its value, the quantum potential would change its value.
2) An experiment was pointed out by John Wheeler is Delayed Choice Experiment, which shows that we can determine the path of particles AFTER each particle has already traversed. It seems like observation can affect past of the particles. This experiment was implemented:
http://images.iop.org/objects/phw/new...
In this image, mirrors divides each particle. If we put half-silvered mirror(which means it only reflects not propagate) on BS2, we can know which way particle has taken and we won't see interference pattern. However, if we don't put a half-silvered mirror, we can't know which way particle has taken and therefore we will see interference pattern on both detectors.
Copenhagen Interpretation
According to Bohr, it is meaningless to ask "what is electron" when we don't observe it. Either we can leave electrons alone and observe an interference pattern, or we can take a peek particles' trajectories and wash out the pattern. Two situations are not contradictory but complementary such as momentum-position complementary. Therefore, Copenhagen Interpretation says it is meaningless to say electron exists on its own(not as a result of an observation).
If an atom is excited at t1, then quantum mechanics can calculate the probability of that it will no longer be excited at t2. All we know the observations of its energy at t1 and t2. We don't need to assume anything between t1 and t2. For example, energy is not an abstract thing but conserved mathematical analogy that observations of mechanical process. What Bohr suggests things like electron, photon, atom... is the same.
This traditional interpretation creates a paradox in it because it gives very importance to observer. Geiger counter, which is an apparatus used to observe, is also made of quantum objects. Troubles arise when we ask where the dividing line comes between quantum(microscopic) and classic(macroscopic) world. Particles don't posses well-defined properties. However, they do after we make a measurement and we can choose which measurements to make, either position or momentum. If you put a particle in a state of given position, and then decide to measure the momentum, you get a particular value, although the value can't be predicted. The rules of quantum mechanics say, a quantum system can evolve in time in two quite distinct ways. When observation is made, waves that were used to interfere with each other have disappeared but one of them. We cannot undo it and restore the original complex wave pattern, which means mathematically "non-unitary". We can considered both apparatus and quantum object as an isolated system. Yet, this also leads into the paradox because we need another apparatus to determine the quantum state the former apparatus and so on. Von Neumann(and Eugene Wigner) concluded that consciousness can be an end to this vicious circle. However, this seems also paradoxical. For example, if we replace a person with the cat in Schrödinger's thought experiment and if the person is in a superposition state(dead and alive) when we open the box(let's say the person is alive) we can ask the person how he felt before we opened the box. Maybe because the person is a conscious, he collapse the wave function. Some say even the cat can be count as an conscious observer. "Drawing line" problem is now between conscious and unconscious.
Many-Universes Interpretation
When we consider the quantum cosmology unless mind is involved, we must think an external apparatus beyond our universe. Hugh Everett proposed a radical interpretation which, it is claimed, requires less assumption than the traditional interpretation. According to Everett, transition occurs because the universe slips into copies where each quantum states are real in each copies. Therefore, the number of copies depends on the number of quantum states. Furthermore, these universes are the same completely except the quantum state. For example, in Schrödinger's thought experiment in one of the universes cat would be alive whereas cat would be dead in the other. A proponent of this interpretation, Bryce DeWitt expressed it as: Every quantum transition taking place in every star, in every galaxy, in every remote corner of the universe is splitting our local world on Earth into myriads of copies of itself. Here is schizophrenia with vengeance. There two major criticism against it. One is that the interpretation has lots of excess metaphysical baggage while we observe only one universe. In defense, proponents say, the interpretation emerges formal rules of quantum mechanics, without making any epistemological hypothesis despite other interpretations. The other is that it is unstable. If our consciousness is confined to one universe at a time, how could we confirm or refute the others? David Deutsch say it can be tested by very intelligent computers in future. Some say this interpretation may also explain why the universe we living looks arranged precisely so that living creatures arise.
The statistical Interpretation
This interpretation abandons what actually goes on in an individual quantum object. Quantum mechanics seems working good statistically, however there is no case to answer as regards the measurement problems. Therefore, there is no way to know what actually happens when a particular measurement takes place.
Uncertainty, Non-locality and Bell's Theorem
Suppose a single stationary particles explodes into two particles. Uncertainty Principle forbids us from knowing position and momentum of either particle definitely at the same time. We choose one or the other to be well defined. However, because of conservation of momentum, we can measure the momentum of a particle to deduce the that of other one and also by symmetry one of particle must move a distance equal to that of the other one(also if particles are photons, their polarization must be the same).
If faster than light communication is false, quantum mechanics must be incomplete. Bell introduced some inequalities to test this idea. To illustrate, the number of black people can't be greater the number of men plus the number of women. If quantum mechanics is true, Bell inequalities must be exceeded(they were in Aspect's experiment). Entanglement is incompatible with objective reality or locality. By objective reality, we mean the reality of the external world that is independent of our observations. By locality, we mean not instantaneous but separable effect. If one wants to accept entanglement, one should leave locality or objective reality.
John Bell: The Aspect experiment did not prove indeterminism of quantum world, it only proved action at a distance. It must certainly be explored that the hypothesis which says mind has an essential role in physics but it certainly has paradoxes in it. Pre-Einstein position of Lorentz and Poincare, Larmor and Fitzgerald is perfectly coherent and consistent with relativity theory. Thus, we should get back the idea of aether because if all Lorentz frames are equivalent, things can go back in time. Quantum theory is a temporary expedient. It's enough reason to dislike the many-universes interpretation that we only observe one universe. The de Broglie-Bohm theory was developed for non-relativistic quantum mechanics. If you try to extend it to the relativistic context, you will have difficulties.
John Wheeler: The complementarity description of Bohr was the only possible objective(rational) description. The many-universes interpretation seemed to represent the logical follow-up formalism of quantum theory. However, there's too much metaphysical baggage carried along with it. It also takes quantum theory as the currency and leaves the observation as a mere secondary phenomenon, the primary concept must be make meaning out of observation. Maybe philosophy is too important to be left to the philosophers. Consciousness has a crucial role. It seems we can influence on which path a photon will take. As Bohr said, we have no right to talk about what photon is doing until we observe it and also the pas has no meaning or existence until it exist as a record, this can be view as we, conscious observers, are responsible for reality. The gravitational lens effect provides us to see what delayed-choice experiment do in cosmological level.
Rudolf Peierls: There is only one interpretation and one way to understand quantum mechanics - Copenhagen Interpretation. Therefore, when you refer to Copenhagen Interpretation, what you really mean is quantum mechanics. Table(a macroscopic object) is not real until we observe it. We can't replace observer with inanimate device. Suppose you have an apparatus that tells you whether a radioactive atom decayed or not by the position of a pointer. To determine the position of the pointer, you need to shine light on it. Bu you only know the possibility of light being reflected. It goes until you become conscious of that experiment has one result. If you put an unconscious observer such as camera, wave packet won't collapse. Universe wasn't unreal(undecided) before us because we have the information of 13 billion years ago. There is no sensible view of hidden variables theory that doesn't conflict with Aspect Experiment. If we don't communicate with other universes, why invent them?
David Deutsch: The Many-Universes Interpretation is that there are parallel universes which include all existing at the same time and normally not communication with each other. However, they have some influence on each other in microscopic level, that's the reason why we postulate them. It is the simplest interpretation of quantum theory because it involves the fewest assumptions in it. That human consciousness has direct effect on the nature is more unacceptable than the parallel universes. The exact number of universes depends on physical theories which we don't know yet but it's safety to think it's very large, probably infinite. In his favorite way of looking, there is an infinite number of universes and this number does not change but content does. Before choice is made, all the universes are identical; when choice is made, they partition themselves into two groups. Everett proposed universe is branching itself, the reason was that if there was a collection of identical universes, he preferred to speak of it as being one universe. The problem of arrow of time is not also solved in this interpretation. The coming together of universes on a small scale can occur, interference experiment provides an indirect evidence of the fusion of two groups universe into one. The way that Everett interprets Double-Slit Experiment is to say there were two groups of universes that in one universe the photon passed through one slit, and in the other the photon passed through the other slit, but later appeared in the same position, which means that the universes were the same again. Physical reality is the set of all universes evolving together, you cannot move one without moving the others. So parallel universes are connected as the universes of past and future. Copenhagen Interpretation fails in quantum cosmology. It's logically inconsistent to imagine observer outside of the universe. Another advantage of the interpretation is that it will work before we know what an observer is, contrary to the other interpretations.
Suppose an artificial observer(such as computer) which observes an interference phenomenon inside his mind. He tries to observe the effect of different internal states of his brain in different universes interacting with each other. These internal states are set up by a special organ which is essentially another quantum memory unit. The observer's mind differentiate itself into two universes. At the intermediate stage, he will write down "I'm here observing one of the two states". Moreover, he will write down the same thing in both universes because he won't tell which of the two states he observes and won't remember. If interference occurs it means Everett's interpretation is true; however, it does not it means conventional interpretation is true, which says all universes but only one will have disappeared.
John Taylor: the ensemble(statistical) interpretation says when we're observing a quantum system what we're actually doing is that we're making a measurement on an aggregate or ensemble of identically system. Hence, our results takes the form of a probability distribution of particular values for that measurement. We're not allowed to describe what is going on for an individual system. For example, in quantum entanglement we can't talk about the spin of an individual particle, we can only say some ensembles(nearby particles) has spin up/down while the other ensembles(far away particles) has opposite. There is a distinction between measuring and preparing. If you're preparing a state of an ensemble, then you know it will have properties identical with that preparation in the future. If you make a measurement, then you will have been able to gather what it was like before the measurement in the past. We can measure an individual electron, however, there will be an infinite range of possibilities. If we take an individual case in Schrödinger's experiment, it's meaningless to ask whether the cat is alive or dead. We can have wave function to describe the whole universe.
David Bohm: The Copenhagen interpretation only gives a formula describing the probability of what can be observed in a piece of apparatus. Yet the apparatus itself is made of atoms, therefore you should use another piece of apparatus to look at it. Every physicist believe that the external world exists. Descartes said that though is enfolded and matter is extended. However, both are enfolded and both unfold, therefore they are similar in their basic structure. Something can unfold either as a wave-like or a particle-like.It's very similar to the mathematics of the hologram. Think a tree grew from a seed. You can't say the tree was in the seed because its structure also depends on environment like matter does. Experiments and the questions we ask are determined by our way of thinking. In quantum theory we're now asking a certain kind of questions and we're getting a certain kind of answer. Faster that light signalling can make paradoxes such as being able to signal our own past. However, the present theories are not the last word and special relativity will be going to an approximation just as Newtonian mechanics. When we discovered new theories, we will get rid of all these paradoxes. Quantum mechanics does not explain anything but describe it. The quantum potential, which is carried as a wave, can affect particles even quiet far away from the slits, it's influence depends on the form not magnitude. For example, the quantum potential is different if second slit is open/close in double-slit experiment. It has never been introduced like tis new kind of wave(called "active information" by Bohm). We have no control over the influences that propagate faster than light therefore it doesn't violate the special relativity. This quantum potential field does not look like electromagnetic field because electromagnetic field is too simple. The Schrödinger's equations are sufficient to explain both the quantum potential and the many-body problem. Bohm doesn't accept physics is only about making models that explain observations. He doesn't accepet even Popper's idea, which say a theory can be regarded as scientific only if it's falsifiable.
Basil Hiley: "If anybody came to me and said 'I want to solve a certain physical problem, I would recommend that they go ahead with the conventional interpretation" he said, even though he was used to work with Bohm on non-local quantum potential. What we have to try and do is to build up a model which is intuitive and quantum mechanics seems completely counterintuitive. The model(quantum potential) was originated by de Broglie and subsequently developed by David Bohm. In this model, there is an actual particle that has both a definite momentum and a definite position and the wave function does not represent probability but a real field. The field can influence the behaviour of this or other particles, the motion can be derived by Schrödinger's equation. When an electron pass through slits, the result on the other side looks like as if two waves made an interference with each other. Contrary to orthodox theory, the wave is really an average of how a beam individual electron behave, and the intensity of the wave corresponds to the number of electrons arriving at that particular spot in a given time. Another contradiction with orthodox theory is that quantum potential enables you to calculate the set of individual trajectories that give rise the interference pattern. it seem quantum potential gives some information about environment to the particle. Therefore, one can regard the wave as a field of information more that a physical field. It's like direction of a ship's depending on what it receives information from environment by radar waves. Richard Feynman had already pre-empted (us) in saying that he thought of a point in space-time being like a computer with an input and output connecting neighbouring points. So the electron may act like a computer. The motive power that decides how particle act like, of course, comes from the quantum potential itself. The quantum potential does not violate special relativity because it offers an absolute in the background, the quantum aether. In quantum formalism state function for the cat at the end of experiment is a linear superposition of a cat alive and a cat dead. These two states exist together in some way. Hiley doesn't see why mind should be introduced into physics at this level, He's also not keen on the many-universes interpretation because we seem to be producing many universes of which only one is observed by us. Uncertainty that Heisenberg introduced is caused by the apparatus. The reason why there is Planck's constant in this uncertainty is that the constant is not relevant. It seems it is because if you put Planck's constant equal to zero, you will get classical mechanics from the quantum formalism. Moreover, the quantum potential contains Planck's constant, therefore if Planck's constant changed its value, the quantum potential would change its value.
This entire review has been hidden because of spoilers.
December 7, 2025
朱利安‧布朗、保羅‧戴維斯著。史領空譯。
月亮只在有人看它時才存在
這本書是有關量子力學的詭異特性以及對這些詭異特性的多種哲學詮釋的介紹。
目前我只注意〈導讀〉、〈第一章〉、〈第五章〉，因為如果認為哥本哈根詮釋是對的，就只需看這幾章就好了。其他哲學觀點似乎都有點玄虛，我暫時不想花時間涉入太深。值得注意的是高涌泉的導讀，頗為精要的把量子力學的來龍去脈解釋的比較淺顯，是篇很好的介紹文章。
對量子力學的詭異特性，金觀濤《我的哲學探索》描述大約於下：
認識論要解決的是主客體問題。所謂客體，即物理實在，即它總是“同時”具有各種“確定”的屬性。如體積、位置、速度等等。但量子力學卻告訴我們，“量子”(指包含光子、電子等組成世界的基本粒子，以下均以電子為例)的“存在”並非如此。量子力學的基本定律“測不準原理”(uncertainty principle)就指稱：電子不可能同時具有確定的位置與速度。當然，所謂“確定”關係到“精確度”問題。公式的意義是，如果你把電子速度測的無限準，那麼就表示關於電子位置的誤差會變得無限大；反之，你如果把位置測的無限準，那麼速度的誤差就會無限大。我們永遠沒辦法“同時”把一個電子的位置和速度交代的無限精確。電子的存在不同於宏觀世界中物體的存在，它是客體，卻是一個模糊的客體。當我們犧牲某��程度的精確性之後，我們可以得到電子所處位置和速度的“差不多”表述，差不多的意思就是“不確定”，是量子物體的本性。
海森堡對測不準原理的解釋是，當人在觀察(自然是透過儀器來觀察)客體時，總是存在著對客體的擾動，在宏觀物體，這種擾動可以忽略不計，但在電子，這種擾動就變得不可忽略了。例如，我們用一種儀器測量電子的位置，這個測量必然會干擾它的運動，使它的速度成為不確定。反之，我們用一種儀器測量電子的速度時，又會干擾到電子的位置，使它的位置變成不確定。也就是說，在同一時間測量電子位置和速度這兩個動作根本是互有妨礙的。這不是實驗中諸如儀器設計等的問題，而是量子物體的“天性”如此。確定的位置和速度(嚴格來說是“動量”，因為這個詞不那麼平易，所以我在上面一律改用速度)、能量和時間、波動���和粒子性等，正如平放在桌面的硬幣，正反面不可能同時呈現(我問過DS，他說這個海森堡觀點已被證明為非)。
接下來的問題是，如果我們“不觀察”呢？我們若不觀察，電子就會具有確定的位置和速度了嗎？我們不看月球時，可以有把握的說月球具有確定的位置和速度，但電子呢？量子力學的哥本哈根詮釋(目前對量子力學的主流詮釋)認為，在量子的範疇裡，你的測量行為會導致一個結果，但這個結果並不代表就是電子的“實在”，而是由你的測量行為和電子的本性結合的結果。也就是說，若你不觀察，你根本無法預測電子的屬性，也許它根本不是電子。它顯示電子相，是加入你的觀察的結果。他們認為，當人不觀察電子時，去談電子是什麼，是沒有意義的。這就是說：“存在”離不開人的感知。量子力學似乎將我們導向了“主觀唯心論”。更誇張的是，如果電子的客觀存在依賴於人類觀測時的波函數縮併(collapse of the wave function)，那麼這個由量子物體組成的人，或這個由量子物體組成的宇宙，又是在誰的觀測下縮併為客體存在呢？是上帝吧？於是量子力學似乎又將我們導向了“客觀唯心論”。
金觀濤認為，哥本哈根詮釋多半是對的，只是論述還不夠深入。他在1976年發表《論量子力學公理基礎》一文，以黑箱理論對量子力學的認識論意涵做過一番數學推導，要理解這個推導過程不容易，需要一定的量子力學基礎，但要理解它的結論卻很簡單。其實，他的觀點可以用“條件性公理”作一簡單概括。就像水的三態各有其存在的條件，電子要呈現某種確定的性質也是需要條件的。當我們說，電子的狀態依賴於觀察者的建構(指整個觀測行為)時，就只是意謂著這個條件是隱含在整個實驗設計中的。整個實驗設計，“迫使”電子只能呈現出某種確定性。而離開這組條件、離開這個實驗去談電子是什麼，自然是沒有意義的。就好比你問溫度不存在的時候，水是什麼？日常生活中，我們早就熟悉在某些條件下，某物具有某一種性質，而在另一種條件下，它可以具有另一種性質。並且，當兩種條件不能同時並存時，兩種性質自然不能同時存在。但用在測不準原理時我們卻困惑了。金觀濤認為，我們只要詳細分析測量電子動量和位置的裝置，就可以發現它們確實是互相排斥或干擾的。
所以，在條件公理看來，當我們去問，人不觀察電子時，電子是什麼？並不是在問那個無條件的“客觀實在”是什麼，而是在問，在自然條件下(沒有人為控制的實驗條件)電子是什麼？就好比你在問，自然條件下，水處於什麼狀態一樣？因此，當我們考慮觀察者不存在時，被觀察的對象是否存在，實際上只是在作一種條件的變換；把人為控制的條件換成與人無關的條件。存在並非被感知，而是這類的存在必須實行人為控制，如觀測電子。而有些存在則是“不需”實行人為控制的，或人“無法”進行控制的，如觀測月球。那麼，月球就可以不依賴人的建構而存在，電子則依賴人的建構。我們走出了主觀唯心論的陰影，釐清了所謂物理實在的底蘊，那就是：沒有不需條件的存在。
在這個概念下，所謂的波函數縮併或量子纏結(quantum entanglement)也不再那麼神秘。金觀濤認為，我們必能從中發掘實驗設計對電子狀態的條件控制。一切理論的困惑就在於我們認為實驗是可以絕對客觀的。卻不知，任何受控實驗均是一種對觀測對象施行條件控制的過程。例如EPR思想實驗(測量子糾纏)中，粒子分裂飛離所遵循的角動量守恆律，並不僅僅是一種自然定律，而是需要以實驗手段(儀器)加以控制的過程。實驗中，儀器間的相關性可能自始至終便存在，並且不能排除。這裡不存在所謂“幽靈般的超距作用”，而是在觀測過程中，它們便相互影響，以致一旦一方完成觀測，另一方必然也同時顯示相同的結果(不管它們距離多遠)。關於這部分，金觀濤謙虛的認為這還只是他“大膽的猜想”，但在我看來這是相當具有說服力的想法。
月亮只在有人看它時才存在
這本書是有關量子力學的詭異特性以及對這些詭異特性的多種哲學詮釋的介紹。
目前我只注意〈導讀〉、〈第一章〉、〈第五章〉，因為如果認為哥本哈根詮釋是對的，就只需看這幾章就好了。其他哲學觀點似乎都有點玄虛，我暫時不想花時間涉入太深。值得注意的是高涌泉的導讀，頗為精要的把量子力學的來龍去脈解釋的比較淺顯，是篇很好的介紹文章。
對量子力學的詭異特性，金觀濤《我的哲學探索》描述大約於下：
認識論要解決的是主客體問題。所謂客體，即物理實在，即它總是“同時”具有各種“確定”的屬性。如體積、位置、速度等等。但量子力學卻告訴我們，“量子”(指包含光子、電子等組成世界的基本粒子，以下均以電子為例)的“存在”並非如此。量子力學的基本定律“測不準原理”(uncertainty principle)就指稱：電子不可能同時具有確定的位置與速度。當然，所謂“確定”關係到“精確度”問題。公式的意義是，如果你把電子速度測的無限準，那麼就表示關於電子位置的誤差會變得無限大；反之，你如果把位置測的無限準，那麼速度的誤差就會無限大。我們永遠沒辦法“同時”把一個電子的位置和速度交代的無限精確。電子的存在不同於宏觀世界中物體的存在，它是客體，卻是一個模糊的客體。當我們犧牲某��程度的精確性之後，我們可以得到電子所處位置和速度的“差不多”表述，差不多的意思就是“不確定”，是量子物體的本性。
海森堡對測不準原理的解釋是，當人在觀察(自然是透過儀器來觀察)客體時，總是存在著對客體的擾動，在宏觀物體，這種擾動可以忽略不計，但在電子，這種擾動就變得不可忽略了。例如，我們用一種儀器測量電子的位置，這個測量必然會干擾它的運動，使它的速度成為不確定。反之，我們用一種儀器測量電子的速度時，又會干擾到電子的位置，使它的位置變成不確定。也就是說，在同一時間測量電子位置和速度這兩個動作根本是互有妨礙的。這不是實驗中諸如儀器設計等的問題，而是量子物體的“天性”如此。確定的位置和速度(嚴格來說是“動量”，因為這個詞不那麼平易，所以我在上面一律改用速度)、能量和時間、波動���和粒子性等，正如平放在桌面的硬幣，正反面不可能同時呈現(我問過DS，他說這個海森堡觀點已被證明為非)。
接下來的問題是，如果我們“不觀察”呢？我們若不觀察，電子就會具有確定的位置和速度了嗎？我們不看月球時，可以有把握的說月球具有確定的位置和速度，但電子呢？量子力學的哥本哈根詮釋(目前對量子力學的主流詮釋)認為，在量子的範疇裡，你的測量行為會導致一個結果，但這個結果並不代表就是電子的“實在”，而是由你的測量行為和電子的本性結合的結果。也就是說，若你不觀察，你根本無法預測電子的屬性，也許它根本不是電子。它顯示電子相，是加入你的觀察的結果。他們認為，當人不觀察電子時，去談電子是什麼，是沒有意義的。這就是說：“存在”離不開人的感知。量子力學似乎將我們導向了“主觀唯心論”。更誇張的是，如果電子的客觀存在依賴於人類觀測時的波函數縮併(collapse of the wave function)，那麼這個由量子物體組成的人，或這個由量子物體組成的宇宙，又是在誰的觀測下縮併為客體存在呢？是上帝吧？於是量子力學似乎又將我們導向了“客觀唯心論”。
金觀濤認為，哥本哈根詮釋多半是對的，只是論述還不夠深入。他在1976年發表《論量子力學公理基礎》一文，以黑箱理論對量子力學的認識論意涵做過一番數學推導，要理解這個推導過程不容易，需要一定的量子力學基礎，但要理解它的結論卻很簡單。其實，他的觀點可以用“條件性公理”作一簡單概括。就像水的三態各有其存在的條件，電子要呈現某種確定的性質也是需要條件的。當我們說，電子的狀態依賴於觀察者的建構(指整個觀測行為)時，就只是意謂著這個條件是隱含在整個實驗設計中的。整個實驗設計，“迫使”電子只能呈現出某種確定性。而離開這組條件、離開這個實驗去談電子是什麼，自然是沒有意義的。就好比你問溫度不存在的時候，水是什麼？日常生活中，我們早就熟悉在某些條件下，某物具有某一種性質，而在另一種條件下，它可以具有另一種性質。並且，當兩種條件不能同時並存時，兩種性質自然不能同時存在。但用在測不準原理時我們卻困惑了。金觀濤認為，我們只要詳細分析測量電子動量和位置的裝置，就可以發現它們確實是互相排斥或干擾的。
所以，在條件公理看來，當我們去問，人不觀察電子時，電子是什麼？並不是在問那個無條件的“客觀實在”是什麼，而是在問，在自然條件下(沒有人為控制的實驗條件)電子是什麼？就好比你在問，自然條件下，水處於什麼狀態一樣？因此，當我們考慮觀察者不存在時，被觀察的對象是否存在，實際上只是在作一種條件的變換；把人為控制的條件換成與人無關的條件。存在並非被感知，而是這類的存在必須實行人為控制，如觀測電子。而有些存在則是“不需”實行人為控制的，或人“無法”進行控制的，如觀測月球。那麼，月球就可以不依賴人的建構而存在，電子則依賴人的建構。我們走出了主觀唯心論的陰影，釐清了所謂物理實在的底蘊，那就是：沒有不需條件的存在。
在這個概念下，所謂的波函數縮併或量子纏結(quantum entanglement)也不再那麼神秘。金觀濤認為，我們必能從中發掘實驗設計對電子狀態的條件控制。一切理論的困惑就在於我們認為實驗是可以絕對客觀的。卻不知，任何受控實驗均是一種對觀測對象施行條件控制的過程。例如EPR思想實驗(測量子糾纏)中，粒子分裂飛離所遵循的角動量守恆律，並不僅僅是一種自然定律，而是需要以實驗手段(儀器)加以控制的過程。實驗中，儀器間的相關性可能自始至終便存在，並且不能排除。這裡不存在所謂“幽靈般的超距作用”，而是在觀測過程中，它們便相互影響，以致一旦一方完成觀測，另一方必然也同時顯示相同的結果(不管它們距離多遠)。關於這部分，金觀濤謙虛的認為這還只是他“大膽的猜想”，但在我看來這是相當具有說服力的想法。
October 22, 2020
This has been a good read. The author has put a lot of time and effort. Being a writer myself, I find it commendable. The content is decent and keeps you hooked for a long time. And some parts are simply minds blowing. I look forward to reading more books like this. All in all, a good experience for an avid reader like me.
December 19, 2025
สำหรับผู้อ่านที่มีองค์ความรู้ก่อนแล้ว คงสนุกมาก
February 20, 2014
The real (unreal) world of quantum theory; views of eight active researchers
Anyone who is interested to understand reality (universe, consciousness and life), and laws of physics applicable to them must be interested in learning about the laws quantum mechanics. A number of books are available, and this one stands out as a book for good introduction. The authors' interview eight physicists who are actively engaged in research and the profoundness of the universe and the concept of quantum reality begins to unravel as you progress through the book. The book is written for common readers but you must appreciate basic quantum physics experiments, whose results are discussed throughout the book. There are nine chapters, and the first chapter introduces the basics of quantum theory.
Matter at the most fundamental level has both particle and wave nature (wave-particle duality), because some experiments illustrates the particle properties, and other experiments shows the wave properties. In addition, the Heisenberg Uncertainty principle postulates that the position and momentum of a fundamental particle are not determinable at the same time. This is not due to experimental limitations but inherent characteristic of matter, an intrinsic fuzziness of the subatomic world. Therefore it follows, in experiments measuring the path of fundamental particles; the famous two - slit electron experiment of Thomas Young; identical experiments yield different results. It is a common experience in the real world that the laws of cause and effect dictates common sense, for example, a planet in its orbit uses a well defined path and its position can be predicted at any give time, but in quantum world, this is uncertain and we can only discern the point of departure and point of arrival of an electron in an experiment but nothing about the actual path.
There are five major interpretations of quantum theory, they are; a. Copenhagen interpretation; b. Hugh Everett's many universes interpretation; c. Wigner's interpretation; d. Hidden variables interpretation and quantum potential; and e. Ensemble (statistical) interpretation. Copenhagen interpretation is considered as the official view. According to this, reality of classical world is ambiguous and non-specifiable. It gives subatomic particles an abstract mathematical status but does not provide reality in full common sense of the word. In classical thought the universe is independent of an observer; it exist no matter we observe that or not. This is objective reality that squares off with common sense perception. This is precisely the concept that Bohr challenged in his interpretation that objective reality doesn't exist per se until measurements are performed. In general, a quantum state may contain an infinite number of superimposed quantum states. The act of observation and measurement will result in one quantum state and others disappear instantaneously. Many universes interpretation of Hugh Everett proposes that superposition of wave function result in splitting the universe into multiple units each corresponding to one particular wave function or one state. The observer also splits into the same number of units and each universe will have a copy of the observer.
According to Wigner's interpretation, the quantum phenomenon does not happen until reality sets into the consciousness of the observer, but John Wheeler states that realty may have occurred but not put to use until this information is communicated.
Ensemble (statistical) interpretation which implies that any quantum mechanical measurement made is made on an ensemble of identically prepared systems. Hence the results of experiment take the form of a probability distribution of particular values for the measurement. This interpretation looks at the statistics and do not care about individual event. Hidden variables interpretation postulates that a particle like an electron has a potential called quantum potential (QP) which is a new property. Its effect does not depend on its magnitude but only on its form (particle or wave nature) so that it may have big effects over long distances. This wave (QP) also carries experimental arrangement with it and also the states of all other particles in the system. This interpretation also suggests that a particle has both position and a definitive momentum, and QP modifies classical behavior of particles to quantum behavior.
The negative feature of the book is that the authors do not discuss the results of experiments they describe (see pages 11, 16, 19, and 40)
Anyone who is interested to understand reality (universe, consciousness and life), and laws of physics applicable to them must be interested in learning about the laws quantum mechanics. A number of books are available, and this one stands out as a book for good introduction. The authors' interview eight physicists who are actively engaged in research and the profoundness of the universe and the concept of quantum reality begins to unravel as you progress through the book. The book is written for common readers but you must appreciate basic quantum physics experiments, whose results are discussed throughout the book. There are nine chapters, and the first chapter introduces the basics of quantum theory.
Matter at the most fundamental level has both particle and wave nature (wave-particle duality), because some experiments illustrates the particle properties, and other experiments shows the wave properties. In addition, the Heisenberg Uncertainty principle postulates that the position and momentum of a fundamental particle are not determinable at the same time. This is not due to experimental limitations but inherent characteristic of matter, an intrinsic fuzziness of the subatomic world. Therefore it follows, in experiments measuring the path of fundamental particles; the famous two - slit electron experiment of Thomas Young; identical experiments yield different results. It is a common experience in the real world that the laws of cause and effect dictates common sense, for example, a planet in its orbit uses a well defined path and its position can be predicted at any give time, but in quantum world, this is uncertain and we can only discern the point of departure and point of arrival of an electron in an experiment but nothing about the actual path.
There are five major interpretations of quantum theory, they are; a. Copenhagen interpretation; b. Hugh Everett's many universes interpretation; c. Wigner's interpretation; d. Hidden variables interpretation and quantum potential; and e. Ensemble (statistical) interpretation. Copenhagen interpretation is considered as the official view. According to this, reality of classical world is ambiguous and non-specifiable. It gives subatomic particles an abstract mathematical status but does not provide reality in full common sense of the word. In classical thought the universe is independent of an observer; it exist no matter we observe that or not. This is objective reality that squares off with common sense perception. This is precisely the concept that Bohr challenged in his interpretation that objective reality doesn't exist per se until measurements are performed. In general, a quantum state may contain an infinite number of superimposed quantum states. The act of observation and measurement will result in one quantum state and others disappear instantaneously. Many universes interpretation of Hugh Everett proposes that superposition of wave function result in splitting the universe into multiple units each corresponding to one particular wave function or one state. The observer also splits into the same number of units and each universe will have a copy of the observer.
According to Wigner's interpretation, the quantum phenomenon does not happen until reality sets into the consciousness of the observer, but John Wheeler states that realty may have occurred but not put to use until this information is communicated.
Ensemble (statistical) interpretation which implies that any quantum mechanical measurement made is made on an ensemble of identically prepared systems. Hence the results of experiment take the form of a probability distribution of particular values for the measurement. This interpretation looks at the statistics and do not care about individual event. Hidden variables interpretation postulates that a particle like an electron has a potential called quantum potential (QP) which is a new property. Its effect does not depend on its magnitude but only on its form (particle or wave nature) so that it may have big effects over long distances. This wave (QP) also carries experimental arrangement with it and also the states of all other particles in the system. This interpretation also suggests that a particle has both position and a definitive momentum, and QP modifies classical behavior of particles to quantum behavior.
The negative feature of the book is that the authors do not discuss the results of experiments they describe (see pages 11, 16, 19, and 40)
February 4, 2024
Mindblowing! Need to read it many more times to understand it.
March 5, 2017
A fantastic book with different points of view from some of the eminent physicists of the 20th century. The Copenhagen interpretation, many worlds interpretation, Schrodinger's kittens and the discussion about God Doesn't Play Dice - all very interesting and thought provoking. Thanks to SVNIT for providing this gem of a book.
November 20, 2025
[EDIT: upon a second read (with a physics degree now lol), i still think this book is cool! but not as mindblowing, maybe that’s to be expected now]
god this book is amazing.
quantum physics is simply fascinating, and reading interviews with some of the most prominent physicists in the field on their controversial stances is simply mind-blowing. Every physicist (obviously) saw their own POV as the right one, and seeing 2 completely contrasting perspectives (ie: things don't exist until observed (Wigner) VS reality exists beyond whether or not we observe it (Einstein)) and the explanations behind why both could be correct . . . wow. the exploration into consciousness and what defines observations (ie: regarding Wigner's interpretation, does a camera count as "observing" something? or only humans?) and whether that itself can be affected by quantum level phenomena - super cool!!!
god this book is amazing.
quantum physics is simply fascinating, and reading interviews with some of the most prominent physicists in the field on their controversial stances is simply mind-blowing. Every physicist (obviously) saw their own POV as the right one, and seeing 2 completely contrasting perspectives (ie: things don't exist until observed (Wigner) VS reality exists beyond whether or not we observe it (Einstein)) and the explanations behind why both could be correct . . . wow. the exploration into consciousness and what defines observations (ie: regarding Wigner's interpretation, does a camera count as "observing" something? or only humans?) and whether that itself can be affected by quantum level phenomena - super cool!!!
May 13, 2008
this totally changed my understanding of Quantum mechanics. I do not know enough to make judgments about the various different theories, but each was such an interesting and provocative explanation of reality, that it really made me think.
I hope there is a subsequent volume that looks at how the "string" crumbles so to speak.
I hope there is a subsequent volume that looks at how the "string" crumbles so to speak.
April 6, 2014
This interview transcript from the Ghost in the Atom BBC radio show has some interesting nuggets from the likes of John Bell, David Bohm, Basil Hiley and other physicists. The first part of the book is a light summary of quantum mechanics leading into the interviews. Not the best introduction to the topic, but provides color to some interpretations of quantum theory.
November 27, 2016
Fascinating but somewhat above the level of the general reader like me. The final chapter with David Hiley I found to be a little more understandable than those before. A lot of the time the book enters into philosophical debate about the true nature of reality which often became a struggle to follow. However, I would still recommend it to anyone who seeks to enhance their knowledge as I do.
May 25, 2008
I dig this stuff.
June 14, 2013
Najbardziej podoba mi się teoria światów równoległych. Realizuje się taki, który odpowiada naszej świadomości : ))
September 11, 2015
A bit old-fashioned about quantum interpretation, it knows how to treat deep question in a easy way to explain it
Read
February 13, 2015530.12 D2571 1986
May 8, 2015
From interviews (BBC I think) with pioneering quantum physicists. Mind boggling.
Displaying 1 - 24 of 24 reviews