----- Original Message ----- From: "Warren Ockrassa" <[EMAIL PROTECTED]> To: "Killer Bs Discussion" <[email protected]> Sent: Friday, March 04, 2005 12:09 PM Subject: Re: quantum darwin?
> On Mar 3, 2005, at 11:24 PM, Dan Minette wrote: > > > But, you miss why QM is defended as it is. The > > reaction is as though you said "but evolution is just a theory." What > > would be helpful in thinking about this is asking why Feynman's > > response > > was to say "shut up and calculate" instead of pursuing the same > > intuative > > path Einstein did....and why his sucessors agreed with that assessment. > > Either you missed most of what I wrote or I didn't express it > correctly. I'm not disputing that the equations in QM seem to show the > things they seem to show. What I am suggesting is that the wrong > conclusions are being reached, and that it could be because we're > missing something fundamental. I'm think I see where you are coming from. I've been having this discussion with folks who've made similar comment for years, now. There is one important feature concerning new theories that is fairly evident to those of us who've taken 6+ years of classes in physics, and probably is not apparent to those who haven't had to do that. Older theories are not rejected when data requires new theories; they are kept as special limit value cases of the new theories. Let me give one example. As you know energy of an object in a reference frame, according to classical mechanics is (1/2)mv^2. In relativistic mechanics, the total energy is mc^2, where m is the relativistic mass. How does this work out. Well, the relativistic mass is m0/sqrt(1-(v/c)^2), where m0 is the invarient mass, or the rest mass. Expanding that into a series we have mr= m0 + 1/2m(v/c)^2...... For low v, higher order terms are negligable. So, dropping those higher order terms, we have for the total energy, (m0 + 1/2m(v/c)^2)*c^2 =m0c^2 + 1/2mv^2. The second term is classical kinetic energy. Classical mechanics, as well as classical electrodynamics are still taught in all graduate schools. They are not false in the sense that the caloric theory of heat is false, they are just valid to a certain precision and over certain ranges. In the same manner, when Electroweak was developed, QCD was not regulated to the trashbin. Rather, people just looked for small effects of the mixing between electromagnetic and weak forces. They even found them in atomic physics, which I thought was neat. So, I would certainly hope that John Baez and friend's work in foamy space continues to pay off and that we will have a rough outline of quantum gravity in the next 5-25 years. When that happens, present theories will be seen as special cases of the new, more general theory. It will probably take a lot longer to formally derive them, but I would guess that is doable. But, when it happens, you can bet that the present theories will survive as special cases of the new theories. Over the ranges of precision, energies, size, etc. that they have been valid, they will continue to be valid. While nothing in the future is absolutely certain, it would be akin to going back to the caloric theory of heat or electromagnetic waves propegating in a material aether to go back to classically behaving particles. The most important reason for this is the fact that local hidden variable theories have been experimentally falsified. Thus, numerous experiments would have had to have gotten the wrong results for there to be local hidden variable theories. > There isn't a physicist working in QM today who won't say that QM is > incomplete. In other words, we don't yet have the Grand Unified Theory of Everything. Sure, no one will claim that we have QM gravity, for example, or that we've nailed down QCD like we have QED. >It's inelegant, It's extremely elegant, IMHO. For example, Classical Electrodynamics has been formally deduced from QED. But, I can see how popular descriptions will not be elegant. >it has no provision for gravity, and there > are (last I checked) eleven possible and totally different > interpretations of what QM "means" in the universal context. Well, I know of four main groups: Copenhaguen, MWI, one that involves backwards in time signals, and one that involves FTL signals in some unknown fixed reference frame. The biggest group among physicists are the interpretation agnostics: shut up and calculate. After that, its Copenhaguen and MWI that has the vast majority, with only a few professionals in the last two groups. But, that is a comment on the meta-physical position of the physicists. Since each interpreation, by definition, is a description of the exact same data, the differences between the interpreations are philosophical, not scientific. > There are apparent self-contradictions as well. I referred earlier to > the slit experiment's being reproduced on the time axis. I've looked the abstracts for papers on quantum effects with moving detectors, and I don't think that's exactly what was meant. Moving the detectors with a velocity relative to the lab means that the spacetime reference frame for the detector is rotated with respect to the lab. >If there > really is such a thing as qD and "state pointers", how can the slit > experiment along the time axis work? The easiest explaination is that, for relativistic quantum mechanics, causality is given as "spacelike operators must commute." I haven't gone through the formalism to be sure, but I think that the answer is that, when you look at both the experimental and theoretical work, you will find that this requirment is satisfied. One can easily get unnecessary complicatons and contradictions into QM when one translates from the formalism that actually describes what is going on into classical metaphors. > An incomplete set of equations with multiple interpretations and > apparently contradictory outcomes is not a basis on which to judge > larger issues about the universe. You seem to think I'm taking a great > leap of faith here, but I'm not the one acting on faith, or at least I > don't see how I am. Not by pointing out that QM is probably telling us > more than we realize about *ourselves* than it ever will about the > universe we live in. Let me restate a point, because you appear to have missed it. When one is making a distiction between reality as it is apart from from our observations, and the best understanding we obtain from observations, the typical nomenclature is to use "realty" for the former, and "the universe" for the totality of the latter. You earlier mentioned that there are no things in themselves. I am guessing that you had a non-standard term for that. In a classical relistic understanding the sun, moon, planets, etc. are considered things-in-themselves. The earth exists on its own; it orbits the sun by itself, etc. When one sees the limits to our observations, this philosophical assumtion is usually questioned. I handle it by taking a Kantiant worldview. Your posts seem to indicate an attempt to answer it by a semi-realism....the consistancy of which I question. If one were to say that the objects of our perceptions relate to but are not the things that exist apart from us, then one can easily say QM does not describe reality. It desribes observation, which is all science is supposed to do. The external validity of our observations cannot be tested via our observations, no more than one calibrates a density tool against itself. Now, it is possible for observations to give us hints that we are at the limits of perception, but that's a different point. > Which, for the record, we do not make up as we perceive it. I can think > of at least two very practical thought experiments to prove that > assertion beyond reasonable argument. Thought experiments, set up against observations and real experiments, are always tricky. :-) Dan M. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
