Tweet
The comments about the global vs. local symmetries above are valid for the theories as we know them today. If a very large symmetry is relevant for the theory of everything, something about the separation to local and global symmetries must be generalized. Morally, it is true that the unified structure of string theory also unifies its symmetries, but it is harder to see technically how a particular large group could be relevant for the whole picture and why it would be exactly this group and not others. The intriguing idea to get "all of physics" from one very large group (such as one of the groups beloved by Thomas Larsson) remains an unsuccessful speculation.
There are errors in Lee's reasoning on page 30 and around that are too numerous to enumerate. Lee does not distinguish effective theories and UV complete theories; he claims that there are no good interacting quantum field theories above 4 dimensions (what about the (2,0) in d=6?) and so on. I don't know how anything reliable can arise from this philosophizing if one half of the input is just plain wrong. In my opinion, it is enough to overlook one error in order to destroy an argument. Whether or not a 6-dimensional quantum field theory may be UV complete and interacting is an important question, and the answer is Yes. It may not be an expansion around a gaussian fixed point; but it is a consistent theory with operators and their correlators nevertheless.
Fortunately, these technical points are completely independent from the general discussion about the anthropic hope, which is why I can easily agree with Lee's comments about the anthropic hope once again.
In the following section, Lee unifies relationism not only with reductionism but also with Darwin's theory. While I also enjoy these deep ideas about "metaunification", let me admit that similar constructions proposed by others usually look weird to me. Natural selection could possibly share something with relationism but it is definitely too vague to be of any use. Incidentally, Lee's prediction that the parameters of our Universe are optimized for black hole prediction has been safely falsified. It is easy to adjust some parameters in such a way that we produce many more black holes than those seen around.
Cosmological constant puzzle
It's interesting to see a debate about the C.C. problem that is based on four speculations all of which seem completely vacuous and flawed. Statements such as "the C.C. problem is just an artifact of the evil background-dependent thinking" look ridiculous. No doubt, the background dependence is also responsible for the latest terrorist attacks. But such an emotionally loaded combination of words does not show how to calculate the right (tiny) value of the cosmological constant in a theory that contains the known particle physics - which is the true content of the C.C. problem. Some people apparently think that a solution to the C.C. problem means to construct a grammatically correct English sentence that contains a quote by a 16th century philosopher as well as the happy end that the C.C. problem is eventually solved. I beg to differ.
"Relational quantum theory"
On page 37 Lee starts an attack against the quantum theory itself. It's hard for me to read this kind of material. There is one valid point - that Bohr argued that the boundary between the "classical observer" and the "quantum observed object" may be drawn more or less anywhere which was not satisfactory. Today, we solve this question by decoherence that may be used to calculate the scale at which the classical concepts become a good approximation and the quantum coherence and interference disappears because of the interactions with the environment. Decoherence is a part of the modern neo-Copenhagen interpretations, especially the picture based on Consistent Histories.
The emergence of the classical world from the universal framework of quantum mechanics was a well-defined puzzle associated with the interpretation of quantum mechanics - one that has been solved. It is much harder to see which problems Lee is trying to solve now but I suspect that they are not my problems.
Lee combines various valid but usually invalid objections against various interpretations of quantum mechanics with relationism and cosmology. Because the length scale above which the meaning of the text seems to evaporate is around 1-3 sentences, I can't unfortunately say anything nice about these comments. As far as I can say, "relational quantum theory" is an incoherent conglomerate of weird assertions about quantum theory from people who have never understood it and who kind of confuse the lessons of relativity with the lessons of quantum mechanics. Concerning the "relational approaches to go beyond quantum theory", let me just state that as far as I can say, there exist no approaches to go beyond quantum theory (certainly not "relational ones") and all statements I have seen that claim the opposite are rubbish.
While the word "rubbish" may sound harsh, you should not forget that if you rearrange the electrons and nucleons in rubbish properly, you may obtain anything, including a piece of gold. This is what many of us should try to do with these questions.
See also Moshe Moshe Rozali's comments about background independence that are pretty much equivalent to mine.
(The End)
There are errors in Lee's reasoning on page 30 and around that are too numerous to enumerate. Lee does not distinguish effective theories and UV complete theories; he claims that there are no good interacting quantum field theories above 4 dimensions (what about the (2,0) in d=6?) and so on. I don't know how anything reliable can arise from this philosophizing if one half of the input is just plain wrong. In my opinion, it is enough to overlook one error in order to destroy an argument. Whether or not a 6-dimensional quantum field theory may be UV complete and interacting is an important question, and the answer is Yes. It may not be an expansion around a gaussian fixed point; but it is a consistent theory with operators and their correlators nevertheless.
Fortunately, these technical points are completely independent from the general discussion about the anthropic hope, which is why I can easily agree with Lee's comments about the anthropic hope once again.
In the following section, Lee unifies relationism not only with reductionism but also with Darwin's theory. While I also enjoy these deep ideas about "metaunification", let me admit that similar constructions proposed by others usually look weird to me. Natural selection could possibly share something with relationism but it is definitely too vague to be of any use. Incidentally, Lee's prediction that the parameters of our Universe are optimized for black hole prediction has been safely falsified. It is easy to adjust some parameters in such a way that we produce many more black holes than those seen around.
Cosmological constant puzzle
It's interesting to see a debate about the C.C. problem that is based on four speculations all of which seem completely vacuous and flawed. Statements such as "the C.C. problem is just an artifact of the evil background-dependent thinking" look ridiculous. No doubt, the background dependence is also responsible for the latest terrorist attacks. But such an emotionally loaded combination of words does not show how to calculate the right (tiny) value of the cosmological constant in a theory that contains the known particle physics - which is the true content of the C.C. problem. Some people apparently think that a solution to the C.C. problem means to construct a grammatically correct English sentence that contains a quote by a 16th century philosopher as well as the happy end that the C.C. problem is eventually solved. I beg to differ.
"Relational quantum theory"
On page 37 Lee starts an attack against the quantum theory itself. It's hard for me to read this kind of material. There is one valid point - that Bohr argued that the boundary between the "classical observer" and the "quantum observed object" may be drawn more or less anywhere which was not satisfactory. Today, we solve this question by decoherence that may be used to calculate the scale at which the classical concepts become a good approximation and the quantum coherence and interference disappears because of the interactions with the environment. Decoherence is a part of the modern neo-Copenhagen interpretations, especially the picture based on Consistent Histories.
The emergence of the classical world from the universal framework of quantum mechanics was a well-defined puzzle associated with the interpretation of quantum mechanics - one that has been solved. It is much harder to see which problems Lee is trying to solve now but I suspect that they are not my problems.
Lee combines various valid but usually invalid objections against various interpretations of quantum mechanics with relationism and cosmology. Because the length scale above which the meaning of the text seems to evaporate is around 1-3 sentences, I can't unfortunately say anything nice about these comments. As far as I can say, "relational quantum theory" is an incoherent conglomerate of weird assertions about quantum theory from people who have never understood it and who kind of confuse the lessons of relativity with the lessons of quantum mechanics. Concerning the "relational approaches to go beyond quantum theory", let me just state that as far as I can say, there exist no approaches to go beyond quantum theory (certainly not "relational ones") and all statements I have seen that claim the opposite are rubbish.
While the word "rubbish" may sound harsh, you should not forget that if you rearrange the electrons and nucleons in rubbish properly, you may obtain anything, including a piece of gold. This is what many of us should try to do with these questions.
See also Moshe Moshe Rozali's comments about background independence that are pretty much equivalent to mine.
(The End)
Commentaire