weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) (03/24/86)
This comes from a debate in net.philosophy about whether existence is the same thing as following physical law. To make the debate a little more interesting, I shall pursue one standard view of modern physics a la John Archibald Wheeler. In particular, I shall suggest that following physical law, as it is now understood, implies that either physical things do not exist or that a non-physical thing does. Those who've seen this sort of stuff before know I am referring to the EPR (Einstein-Podolsky-Rosen) paradox, Bell's theorem, and the experiments of Aspect et al. I will not give any summary of this circle of ideas, merely state one rather common view of the implications. As Pais once said about Einstein: We often discussed his notions on objective reality. I recall that during one walk Einstein suddenly stopped, turned to me and asked whether I believed the moon exists only when I look at it. Why did Einstein ask this question? Do you find the question too trivial? In quantum mechanics this question is rather profound. Observation is what collapses wave-functions. What machinery is behind this? None: "Every attempt, theoretical or observational, to [find] such a [mechanism] has been struck down." As J A Wheeler wonders in his magnif- icent essay "Law without Law": Why not simply say of the route it actually takes, Allah willed it? And willed the outcome of every other individual quantum process? To strike down a proposal of this kind, it has been pointed out more than once, is beyond the power of logic. One has to appeal instead to pragmatism. And as J A Wheeler asks in "Law without Law": How does quantum mechanics today differ from what Bishop George Berkely told us two centuries ago, "Esse est percipi," to be is to be perceived? Does the tree not exist in the forest unless there is someone there to see it? Do Bohr's conclusions about the role of the observer differ from those of Berkeley? Yes, and in an important way. Bohr deals with the individual quantum process. Berkeley--like all of us under everyday circumstances--deals with multiple quantum processes. It is these multiple quantum processes that are at the heart of this new opposition to the naive view of reality. It is now known that one cannot pretend that different quantum events act independently. One can construct a giant Hilbert space, with different directions corresponding to distinct objects, but the quantum collapse occurs universally. Wait, you say, the moon is way out there, and runs independently of us. The earth rotates, and the moon sets, only in allusion. It hasn't disappeared. Maybe some ancient and ignorant myths thought so, but we know better, right? Wrong. The moon is as subject to quantum law as photons. And the reach of quantum law is the entire universe: one can observe a quasar billions of light-years away split in two by gravitational lensing and then run a delayed choice experiment on the double images. Quantum mechanics has a very long reach indeed. As J A Wheeler describes the entire universe: From "nothingness ruled out as meaningless," to the line of distinction that rules it out; from this dividing line to "phenomena"; from one phenomenon to many; from the statistics of many to regularity and structure; these considerations lead us at the end to ask if the universe is not best conceived as a self-excited circuit: Beginning with the big bang, the universe expands and cools. After eons of dynamic development it gives rise to observership. Acts of observer-participancy--via the mechanism of the delayed-choice experiment--in turn give tangible "reality" to the universe not only now but back to the beginning. To speak of the universe as a self-excited circuit is to imply once more a participatory universe. Now this is interesting! Metaphysical questions about which came first abound. If you want to reject this time loop, you must then follow Bishop G Berkeley's argument and conclude that there is an Observer that gives existence to the Universe: no Observer, no wave-function collapse. Wheeler says this Observer is all of us. Rather fortunate then, that we came into existence, so as to give existence to the rest of the Universe. Before this century, quasars did not exist, since no one observed them. Taken literally, this is roughly the view that Creationists take about quasars: God created the Universe 10000 years ago, with light from the quasars also on the way. But how can we talk about quasars existing NOW? The light we see from them is billions of years old. The quasars no longer exist, probably. The expert sees where I'm leading. The notion of time is yet another observer created illusion, based on a choice of coordinate frame. "Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows." There is no time loop, and so there is no problem? My conclusion: we don't really know what "exist" means anymore. Or more accurately, we don't know what the pre-conditions for existence are. We do know that one of them is to be observed. And identifying the observer that gives us and our universe existence is a mystery. Us? We learned what tables and chairs and water and light are composed of, we have lost ourselves on the more basic notion of existence! It used to be so easy: Look at it and see if it's there. The problem now is what happens when you don't look at it. If you refuse to look at the moon, does quantum mechanics force you to conclude it does not exist? To those experts who have been laughing up to now, and know that it is just a bunch of formulae that work out every time, then we agree that physical reality is contingent on mathematical reality. But the latter? It keeps me awake at nights, if I think about it. If I don't think about it, it works OK. In other words, mathematical reality makes more sense when NOT observed, as opposed to physical reality. As J A Wheeler concluded, so will I: Today we demand of physics some understanding of existence itself. ucbvax!brahms!weemba Matthew P Wiener/UCB Math Dept/Berkeley CA 94720
desj@brahms.BERKELEY.EDU (David desJardins) (03/25/86)
In article <12628@ucbvax.BERKELEY.EDU> weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) writes: >This comes from a debate in net.philosophy about whether existence is >the same thing as following physical law. > >To make the debate a little more interesting, I shall pursue one standard >view of modern physics a la John Archibald Wheeler. In particular, I shall >suggest that following physical law, as it is now understood, implies that >either physical things do not exist or that a non-physical thing does. >.......... Rhetorical Question #1: Is the moon physical? Obviously yes. (If the moon is not physical then nothing is, and the word has no meaning!) Rhetorical Question #2: Does the moon exist? Again, obviously yes. Einstein's question, while insightful, is obviously rhetorical. Whatever the word "exists" means, we had better make sure that we include the moon. Non-Rhetorical Question: What is the moon? That is, what is is that we are referring to when we say "the moon"? My answer has to be that it is a quantum wavefunction (or a segment of one) in the enormous Hilbert space we call the universe. So, I don't think I agree with your conclusion. The moon is a physical thing. It is also a quantum wavefunction in a Hilbert space. I do not find these irreconcilable, as you seem to. In particular, when not being observed, "the moon" is no longer an eigenfunction of our observables. It is neither here nor there, but somewhere in between. Nevertheless, I still insist on calling it a *physical* object (as you noted, all other routes lead to paradox...). The only conclusion we can draw is that "physical" does *not* mean that the observables of the object are fixed. Really, even classical uncertainty tells us this. Observable parameters of a physical object can only be measured (i.e. only exist) up to some residual uncertainty. What is so horrible about this? I now feel ready to answer Einstein's question with confidence. The moon doesn't go away when I don't look at it. But it *does* get sort of fuzzy! -- David desJardins
torek@umich.UUCP (Paul V. Torek ) (03/26/86)
For a less mystifying view, see N. Maxwell, ``Are Probabilism and Special Relativity Incompatible?'', _Philosophy of Science_ 198[4?]. He suggests that wave-packet collapse occurs whenever the difference in rest-energy between the possible collapsed states exceeds a certain value. His account reproduces all the empirical successes of orthodox QM but gives different predictions for certain as-yet-untested circumstances. More detailed references available upon request. Warning: I have directed followups to net.philosophy and net.physics only. --Paul Torek torek@umich
weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) (03/27/86)
In article <539@umich.UUCP> torek@umich.UUCP (Paul V. Torek ) writes: >For a less mystifying view, see N. Maxwell, ``Are Probabilism and Special >Relativity Incompatible?'', _Philosophy of Science_ 198[4?]. He suggests >that wave-packet collapse occurs whenever the difference in rest-energy >between the possible collapsed states exceeds a certain value. His account >reproduces all the empirical successes of orthodox QM but gives different >predictions for certain as-yet-untested circumstances. More detailed >references available upon request. If it's not orthodox quantum mechanics, I doubt if it is correct. For one thing, it sounds like yet another hidden-variable theory. I do not consider J A Wheeler's views mystifying in the least. The hardest thing about learning twentieth century physics is not in understanding the new stuff but in forgetting the old stuff. Only with excess mental baggage can you be mystified by Wheeler's views. My own view is that wave-packet collapse is to the twentieth century what the luminiferous ether was to the nineteenth century. The only mystery is what the twenty first century will reveal about how odd our views today really are. ucbvax!brahms!weemba Matthew P Wiener/UCB Math Dept/Berkeley CA 94720
weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) (03/27/86)
In article <12629@ucbvax.BERKELEY.EDU> desj@brahms.UUCP (David desJardins) writes: >In article <12628@ucbvax.BERKELEY.EDU> > weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) writes: >>This comes from a debate in net.philosophy about whether existence is >>the same thing as following physical law. >> >>To make the debate a little more interesting, I shall pursue one standard >>view of modern physics a la John Archibald Wheeler. In particular, I shall >>suggest that following physical law, as it is now understood, implies that >>either physical things do not exist or that a non-physical thing does. >>.......... > > Rhetorical Question #1: Is the moon physical? Obviously yes. (If the >moon is not physical then nothing is, and the word has no meaning!) > > Rhetorical Question #2: Does the moon exist? Again, obviously yes. >Einstein's question, while insightful, is obviously rhetorical. Whatever >the word "exists" means, we had better make sure that we include the moon. Einstein's question was NOT rhetorical. It obsessed him the last 25 years of his life. He believed in what he called 'objective reality', ie, that phenemona exist and occur without requiring the complete description of the observer. This view isolated him from the physics community. He really wanted to know if physicists took the opposing view literally. Hence the "experiment" to detect if the moon exists. > Non-Rhetorical Question: What is the moon? That is, what is is that >we are referring to when we say "the moon"? My answer has to be that it >is a quantum wavefunction (or a segment of one) in the enormous Hilbert >space we call the universe. > > So, I don't think I agree with your conclusion. The moon is a physical >thing. It is also a quantum wavefunction in a Hilbert space. I do not >find these irreconcilable, as you seem to. I do not find them irreconcilable either. But as you and I have different notions of what a 'physical thing' is apparently, it's hard to see where this leaves us. > I now feel ready to answer Einstein's question with confidence. The >moon doesn't go away when I don't look at it. But it *does* get sort of >fuzzy! Yes! ucbvax!brahms!weemba Matthew P Wiener/UCB Math Dept/Berkeley CA 94720
desj@brahms.BERKELEY.EDU (David desJardins) (03/27/86)
In article <539@umich.UUCP> torek@umich.UUCP (Paul V. Torek ) writes: >For a less mystifying view, see N. Maxwell, ``Are Probabilism and Special >Relativity Incompatible?'', _Philosophy of Science_ 198[4?]. He suggests >that wave-packet collapse occurs whenever the difference in rest-energy >between the possible collapsed states exceeds a certain value. What is mystifying is how people can believe stuff like this. Sorry, but this is the kind of artificial bullshit that people to whom physics is too mystifying to understand cook up to make it "simpler." The only reason anyone would believe this is if they can't understand real QM. This reminds me of the morons who believe that "entropy" has some magical significance and that the universe somehow keeps track of what it is everywhere and makes sure that it never decreases. You may laugh, but I have seen it! -- David desJardins
torek@umich.UUCP (Paul V. Torek ) (03/28/86)
In article <12714@ucbvax.BERKELEY.EDU> desj@brahms.UUCP (David desJardins) writes: >In article <539@umich.UUCP> torek@umich.UUCP (Paul V. Torek ) writes: >>For a less mystifying view, see N. Maxwell, ``Are Probabilism and Special >>Relativity Incompatible?'', _Philosophy of Science_ 198[4?]. He suggests >>that wave-packet collapse occurs whenever the difference in rest-energy >>between the possible collapsed states exceeds a certain value. > > What is mystifying is how people can believe stuff like this. Sorry, >but this is the kind of artificial bullshit that people to whom physics >is too mystifying to understand cook up to make it "simpler." The only >reason anyone would believe this is if they can't understand real QM. > This reminds me of the morons who believe that "entropy" has some >magical significance and that the universe somehow keeps track of what >it is everywhere and makes sure that it never decreases. You may laugh, >but I have seen it! > > -- David desJardins You really have shit for brains, don't you? No doubt you haven't even read the article you are criticizing. Flames to /dev/null, --Paul Torek torek@umich
ellis@spar.UUCP (Michael Ellis) (03/28/86)
>Metaphysical questions about which came first abound. If you want to reject >this time loop, you must then follow Bishop G Berkeley's argument and >conclude that there is an Observer that gives existence to the Universe: no >Observer, no wave-function collapse. Wheeler says this Observer is all of >us. Rather fortunate then, that we came into existence, so as to give >existence to the rest of the Universe. Before this century, quasars did not >exist, since no one observed them. Taken literally, this is roughly the >view that Creationists take about quasars: God created the Universe 10000 >years ago, with light from the quasars also on the way. Those who prefer to believe in an objective, independently existing, 10-15 billion year old Rosenesque universe have another option -- to postulate a Cosmic Observer who has been there since the beginning of time, to assure the existence of everything during those periods of our not-looking. -michael Spinoza should be credited with a certain wisdom worthy of imitation. Attributing the name "God" to independent reality strongly marks the difference between that reality and the purely phenomenal reality, and this is quite in agreement, as we saw, with the teaching of modern physics... Spinoza's use of the word God to denote Being.. is the most direct procedure for comprehensibly expressing the idea that Being is not blind mechanics. - Bernard d'Espagnat (In Search of Reality, Springer-Verlag, 1983)
tos@psc70.UUCP (Dr.Schlesinger) (03/28/86)
"Exist" seems to mean that I can use idiom of "physics" to
communicate with others about it, and those with whom I communicate
use the same rules to verify the content of the communication. It
doesn't necessarily "prove" anything more than that about the moon as
the next case suggests.
"Exist" seems to mean that I can use the idiom of spirituality to
communicate with others about it, and those with whom I communicate
use the same rules to verify the content of the communication. If I
report psychic or otherwise transcendental experiences to others AND
they, using the same idion (or "rules") accept my reports, then those
phenomena surely do "exist," even if it's unlikely that I can bump my
head or skin my knee by hitting them.
Tom Schlesinger
Plymouth State College
Plymouth, N.H. 03264
decvax!dartvax!psc70!psc90!tosweemba@brahms.BERKELEY.EDU (Matthew P. Wiener) (03/29/86)
In article <547@umich.UUCP> torek@zippy.UUCP (Paul V. Torek ) writes: >In article <12714@ucbvax.BERKELEY.EDU> desj@brahms.UUCP (David desJardins) writes: >>In article <539@umich.UUCP> torek@umich.UUCP (Paul V. Torek ) writes: >>>For a less mystifying view, see N. Maxwell, ``Are Probabilism and Special >>>Relativity Incompatible?'', _Philosophy of Science_ 198[4?]. He suggests >>>that wave-packet collapse occurs whenever the difference in rest-energy >>>between the possible collapsed states exceeds a certain value. >> >> What is mystifying is how people can believe stuff like this. Sorry, >>but this is the kind of artificial bullshit that people to whom physics >>is too mystifying to understand cook up to make it "simpler." The only >>reason anyone would believe this is if they can't understand real QM. >> This reminds me of the morons who believe that "entropy" has some >>magical significance and that the universe somehow keeps track of what >>it is everywhere and makes sure that it never decreases. You may laugh, >>but I have seen it! >> >You really have shit for brains, don't you? No doubt you haven't even >read the article you are criticizing. Why should he read it, Paul? There are dozens of variants of quantum mechanics published every year, and they turn out to be most useful as scrap paper. I was discussing the philosophy of orthodox quantum mechanics, and as YOUR response is that there's something mystifying going on, I will conclude you don't understand quantum mechanics, philosophy, and/or mysticism. I recall you had trouble understanding many-worlds a few months back. I agree entirely with David, and thought his response was quite restrained. So perhaps you can explain what is going on that you find so mystifying? My point is that a nineteenth century philosophy died when confronted with a twentieth century physics. If you want to cling on to outdated philosophy, that is your problem. Just don't call orthodox quantum mechanics mystifying, and don't propose cures merely to rescue your philosophy. Orthodox quantum mechanics has been one of the most astonishingly accurate of all scientific theories ever proposed. So bye bye objective reality. ucbvax!brahms!weemba Matthew P Wiener/UCB Math Dept/Berkeley CA 94720
torek@umich.UUCP (Paul V. Torek ) (03/31/86)
In article <12765@ucbvax.BERKELEY.EDU> Matthew P. Wiener writes: >Why should he read it, Paul? There are dozens of variants of quantum >mechanics published every year, and they turn out to be most useful as >scrap paper. But they can only be treated as scrap paper AFTER testing them on the points at which they disagree with orthodox QM. THAT'S MY POINT. >I recall you had trouble understanding many-worlds a few months back. I had trouble buying some of the claims that Ken Rimey made for many-worlds. And I was right: some of them turned out to be exaggerated. For example, many-worlds turned out to be not so different after all from the common "misinterpretation" of it. >So perhaps you can explain what is going on that you find so mystifying? The same things Einstein found troubling. >Orthodox quantum mechanics has been one of the most astonishingly accurate >of all scientific theories ever proposed. So bye bye objective reality. I think your farewell to objective reality may be a bit premature. First, "variants" must be tested and proven false. And Maxwell claims that his hypothesis agrees with orthodox QM over a wide range of conditions, and thus can reproduce that "astonishingly accurate" record. Second, not all philosphers agree that QM is incompatible with objective reality. I'll dig up references on the second point. (I haven't seen their arguments, so I'm suspending judgement.) Meanwhile, you might want to look at the article by Bernard d'Espagnat in the Nov 1979 _Scientific American_. He is a physicist who is not ready to say "bye bye" to objective reality. --Paul Torek torek@umich P.S. Sorry about my "shit for brains" remark. It was uncalled for. I still vehemently object to dismissing unothodox variants before they are tested.