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> The rest of your post is discussing philosophy, I'm trying not to be philosophical and wondering if by now we have enough data so that we can talk about purp

> The rest of your post is discussing philosophy, I'm trying not to be philosophical and wondering if by now we have enough data so that we can talk about purpose without being philosophical. Sure, that we have that much data now is a long shot! > What makes you think it was deliberate? It looks like it might be a deliberate case of our being denied information that might let us see behind the curtain, that is, see more of how the universe is working. > (that predicts that no information can propagate faster than the speed of light). How we get from special relativity to that, I want to check out in detail. Also there is the EPR "spooky action at a distance". Sure, the usual statement is that this does not permit communications faster than the speed of light, but I've seen no careful, detailed argument and want to check this out. Also, for what I started with, a photon through a beam splitter, the wave function then in two parts, and then later the wave function parts separated by some large distance, if we have photo detectors for each part of the wave function, then the usual argument/assumption is that at most one detector will get a signal from that photon. So, instantly, across light years, the other half of the wave function is destroyed. But in principle we could detect when the detector got a signal because the other half of the wave function would suddenly not exist and would not have its effect on gravity. We're talking the gravity of half a wave function of a photon; right, small. But in principle .... > Quantum mechanics isn't dice rolling. It is true that there cannot be a local hidden-variables theory of QM, but QM still has incredible predictive power when discussing the probabilities of experiments. Two high energy photons cross paths, there at the same time. Maybe they generate an electron-positron pair, and maybe they don't. That's a roll of the dice. > It is possible in the future that a non-probabilistic view of QM will emerge, it just cannot be both hidden-variables and local. I saw the Bell's inequality part of the MIT introductory QM lectures. After that lecture, I wanted to see a much, much more careful presentation. Yes, yes, yes, I've heard what 99% of the physics community believes; I took more than enough physics to see how such beliefs are passed out. What I want to know is what the heck the truth is, including about far out possibilities, and for that at least I want the arguments, and the math, about the old stuff, solid. > If ants could think, they would probably think they're the most amazing thing they know of in the universe. The only reason we think we're so amazing is because we have no competitor to compare to. Not quite the "only" thing: We have axiomatic set theory as our foundation of math, and there we have pushed hard on its rough edges, e.g., what is decidable. Likely ET can't do better. Then building on set theory, we have math, and just from the Whitehead-Russell stuff we know how that can be verified by just mechanical means, e.g., just symbol substitution. And we know that some new results can be obtained also just by mechanical means. And I have to doubt that ET can do better in the framework -- for specific math results, sure, ET can be 1 million years ahead of us. So, basically, we seem to know how solid reasoning goes. I'm guessing that ET can't do better on the techniques of solid reasoning, that is, ET can come up with terrific theorems we have not found yet but is still limited to the same framework I just outlined. And, ET will have seen all our basic physics and will have to agree with at least 99% of it, no matter how sloppy the MIT QM course is. ET can't disagree with that 99%. For that part of physics, we and ET are in agreement. So, in some fundamental ways, at least the frameworks, methods, paradigms, we are about as good as there can be. That's some of why we look special. And it's some of why we seem to be approaching limits on what we or ET can know about the universe. So, if there is a purpose, then we are seeing about all the evidence there can be about what that purpose might be. So far, we don't see a purpose. But I was asking if there is some more info that lets us start to guess a purpose? > The reason it's 3K is that it has been cooling since the big bang and that's the temperature it happens to be today. If it were any other temperature, would that also be a clue? My point about the 3 K radiation is not that it is not 2 K (as apparently eventually it will be) or 4 K (as apparently it once was) but that it is to us for photons a wall we can't see past. Also the timing is curious: 3 K is darned cold, and it took some astounding detectors to study it; in some years, the temperature will be 2 K, 1 K, etc., and need still more astounding detectors. So, at 3 K, we've come along at about the right time. When big, seemingly independent things agree in time, it looks suspicious. So, we have to suspect that the wall was deliberate. I'm willing to set that guess aside because people are talking about seeing gravitational waves from before the time of the origin of the 3 K radiation -- so the 3 K radiation is only partly a wall. And by analyzing the 3 K radiation, e.g., taking the spacial power spectrum and understanding the acoustic aspects, maybe we can get some clues about before that radiation. Still, to me, that there is this wall of 3 K radiation, in surprising senses uniform, is one heck of a situation. I'm not, but some people got all wound up and called it the face of God! If there is a purpose, maybe from the shockingly surprising 3 K radiation we can get a clue. Uh, maybe shocking conclusions, e.g., a purpose, need shocking data so that from shocking data maybe we should look for shocking conclusions, e.g., a purpose!

cyphar 9y ago
Alright, I'm just going to focus on the physics in your comment. > How we get from special relativity to that, I want to check out in detail. It's a fairly trivial derivation once you get past the fact that Newtonian mechanics doesn't work at relativistic speeds (the big insight Einstein had was his conviction that Maxwell was correct and Newton was wrong). You do it in second-year physics courses (at least, that's when I did it). You can even do it intuitively. If light always propagates at c, no matter what speed you're travelling at, then the Lorentz transformations are the only way that different reference frames are able to agree on measurements. > Also there is the EPR "spooky action at a distance". Sure, the usual statement is that this does not permit communications faster than the speed of light To be fair, this is actually quite hard to wrap your head around. There are definitely papers on the topic if you want to read them, but the effective reason why you cannot communicate using entangled particles is related to the distinction between the phase and group velocities. A phase velocity can be faster than the speed of light, but it carries no information (without also knowing other properties of the wave which travel slower than the speed of light). The orientation of the two particles is (effectively) their relative phase but you can't actually communicate information using it. > Maybe they generate an electron-positron pair, and maybe they don't. That's a roll of the dice. Again, currently we do not have a way of predicting the outcome of an individual experiment, but there's no reason to believe that we will never be able to do so. > We have axiomatic set theory as our foundation of math ... which gives us Godel's incompleteness theorem. Maybe ET has a far more sophisticated basis of mathematics that doesn't permit Godel. I don't know, but it's a bit odd to claim that axiomatic set theory is somehow the holy grail (it has its own problems such as the requirement of the Axiom of Choice). > Still, to me, that there is this wall of 3 K radiation, in surprising senses uniform, is one heck of a situation. We know why that happened though, it's because of inflation.
- graycat 9y ago
  For EPR, as I understand it from my too crude reading, there is an event and two particles are created and fly off in different, maybe from conservation of momentum, opposite directions. So, the two particles are a QM system with one wave function which, however, is in two parts that are separating rapidly. As I understand the usual interpretation of the wave function, there is no, say, definite spin. We don't know what the spin of either particle is, and neither does the wave function or anything else. That is, a definite value of the spin just doesn't exist yet. Then we measure the spin of one of the particles, and that measurement gives us a spin that apparently was determined just at our measurement. Then the wave function of the two particles has to change, and the other particle has its wave function but if we measure its spin we will get what we are supposed to, say, opposite, from what we measured from the first particle. So, the fixing of the spin of the particle we measure second was somehow transmitted faster than the speed of light. Just what was transmitted faster than the speed of light we don't know about, can't detect, and is not physics in any usual sense. Still, say, if we were trying to write a computer program to simulate this, as soon as the first measurement was made, we'd have to stop the simulation clock of the universe, go the other particle, on the simulation clock, infinitely fast, fix that particle's spin, and then continue the simulation. Strange stuff. But, sure, that doesn't tell us how to do communications with EPR "spooky action at a distance". I don't yet know enough QM to make well informed questions about more. I should watch the MIT QM course lectures through to the end (hold my nose on how he does his math) and pick out the more important things they are saying about how wave functions behave, when there are interactions and the wave functions disappear, etc. Yes, pretty much need to assume the axiom of choice, and some of its consequences are tough to swallow. > Again, currently we do not have a way of predicting the outcome of an individual experiment, but there's no reason to believe that we will never be able to do so. Right. So, if we could so predict, what surprising things could we do with that? So, we are being forbidden to do such things. Why? Does this provide a clue about purpose? Right, this is a long way from physics at least now. For why SR says that information cannot be transmitted faster than light, IIRC what you said about the Lorentz transformations can say that just information, of any kind, sent any way, known to current physics or not, would permit a case of time travel or seeing into the future or some such, and we don't want to believe in that. Yes, there is physics, say, the standard model, and first cut it looks quite simple. But the consequences are astounding beyond belief. E.g., we couldn't look at the standard model and see how DNA would work and what it would do, for green plants, earth worms, ..., humans. Heck, just looking at the standard model, we might guess that the universe would be just a fog of hydrogen or something else so simple. Even if we looked at the standard model long enough to conclude that galaxies and stars would form, some stars would explode and create some of the periodic table (the rest created otherwise), condense to planets, it's still tough to see why the planets would be more than, say, just Mars. But, no, DNA happened and after a billion or so years, we happened. That looks so astounding it looks suspiciously like part of a purpose. But you are right, that's not physics yet.

cyphar 9y ago

Alright, I'm just going to focus on the physics in your comment. > How we get from special relativity to that, I want to check out in detail. It's a fairly trivial derivation once you get past the fact that Newtonian mechanics doesn't work at relativistic speeds (the big insight Einstein had was his conviction that Maxwell was correct and Newton was wrong). You do it in second-year physics courses (at least, that's when I did it). You can even do it intuitively. If light always propagates at c, no matter what speed you're travelling at, then the Lorentz transformations are the only way that different reference frames are able to agree on measurements. > Also there is the EPR "spooky action at a distance". Sure, the usual statement is that this does not permit communications faster than the speed of light To be fair, this is actually quite hard to wrap your head around. There are definitely papers on the topic if you want to read them, but the effective reason why you cannot communicate using entangled particles is related to the distinction between the phase and group velocities. A phase velocity can be faster than the speed of light, but it carries no information (without also knowing other properties of the wave which travel slower than the speed of light). The orientation of the two particles is (effectively) their relative phase but you can't actually communicate information using it. > Maybe they generate an electron-positron pair, and maybe they don't. That's a roll of the dice. Again, currently we do not have a way of predicting the outcome of an individual experiment, but there's no reason to believe that we will never be able to do so. > We have axiomatic set theory as our foundation of math ... which gives us Godel's incompleteness theorem. Maybe ET has a far more sophisticated basis of mathematics that doesn't permit Godel. I don't know, but it's a bit odd to claim that axiomatic set theory is somehow the holy grail (it has its own problems such as the requirement of the Axiom of Choice). > Still, to me, that there is this wall of 3 K radiation, in surprising senses uniform, is one heck of a situation. We know why that happened though, it's because of inflation.

graycat 9y ago
For EPR, as I understand it from my too crude reading, there is an event and two particles are created and fly off in different, maybe from conservation of momentum, opposite directions. So, the two particles are a QM system with one wave function which, however, is in two parts that are separating rapidly. As I understand the usual interpretation of the wave function, there is no, say, definite spin. We don't know what the spin of either particle is, and neither does the wave function or anything else. That is, a definite value of the spin just doesn't exist yet. Then we measure the spin of one of the particles, and that measurement gives us a spin that apparently was determined just at our measurement. Then the wave function of the two particles has to change, and the other particle has its wave function but if we measure its spin we will get what we are supposed to, say, opposite, from what we measured from the first particle. So, the fixing of the spin of the particle we measure second was somehow transmitted faster than the speed of light. Just what was transmitted faster than the speed of light we don't know about, can't detect, and is not physics in any usual sense. Still, say, if we were trying to write a computer program to simulate this, as soon as the first measurement was made, we'd have to stop the simulation clock of the universe, go the other particle, on the simulation clock, infinitely fast, fix that particle's spin, and then continue the simulation. Strange stuff. But, sure, that doesn't tell us how to do communications with EPR "spooky action at a distance". I don't yet know enough QM to make well informed questions about more. I should watch the MIT QM course lectures through to the end (hold my nose on how he does his math) and pick out the more important things they are saying about how wave functions behave, when there are interactions and the wave functions disappear, etc. Yes, pretty much need to assume the axiom of choice, and some of its consequences are tough to swallow. > Again, currently we do not have a way of predicting the outcome of an individual experiment, but there's no reason to believe that we will never be able to do so. Right. So, if we could so predict, what surprising things could we do with that? So, we are being forbidden to do such things. Why? Does this provide a clue about purpose? Right, this is a long way from physics at least now. For why SR says that information cannot be transmitted faster than light, IIRC what you said about the Lorentz transformations can say that just information, of any kind, sent any way, known to current physics or not, would permit a case of time travel or seeing into the future or some such, and we don't want to believe in that. Yes, there is physics, say, the standard model, and first cut it looks quite simple. But the consequences are astounding beyond belief. E.g., we couldn't look at the standard model and see how DNA would work and what it would do, for green plants, earth worms, ..., humans. Heck, just looking at the standard model, we might guess that the universe would be just a fog of hydrogen or something else so simple. Even if we looked at the standard model long enough to conclude that galaxies and stars would form, some stars would explode and create some of the periodic table (the rest created otherwise), condense to planets, it's still tough to see why the planets would be more than, say, just Mars. But, no, DNA happened and after a billion or so years, we happened. That looks so astounding it looks suspiciously like part of a purpose. But you are right, that's not physics yet.