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#1
10-08-2006, 02:33 PM
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My apologies ...
... for not posting a political thread, but I found this interesting.
Bot Theory in particle physics: Theological speculation versus practical knowledge Burton Richter October 2006, page 8 To me, some of what passes for the most advanced theory in particle physics these days is not really science. When I found myself on a panel recently with three distinguished theorists, I could not resist the opportunity to discuss what I see as major problems in the philosophy behind theory, which seems to have gone off into a kind of metaphysical wonderland. Simply put, much of what currently passes as the most advanced theory looks to be more theological speculation, the development of models with no testable consequences, than it is the development of practical knowledge, the development of models with testable and falsifiable consequences (Karl Popper's definition of science). You don't need to be a practicing theorist to discuss what physics means, what it has been doing, and what it should be doing. When I began graduate school, I tried both theory and experiment and found experiment to be more fun. I also concluded that first-rate experimenters must understand theory, for if they do not they can only be technicians for the theorists. Although that will probably get their proposals past funding agencies and program committees, they won't be much help in advancing the understanding of how the universe works, which is the goal of all of us. I like to think that progress in physics comes from changing "why" questions into "how" questions. Why is the sky blue? For thousands of years, the answer was that it was an innate property of "sky" or that the gods made it so. Now we know that the sky is blue because of the mechanism that preferentially scatters short-wavelength light. In the 1950s we struggled with an ever-increasing number of meson and baryon resonances—all apparently elementary particles by the standards of the day. Then Murray Gell-Mann and George Zweig produced the quark model, which swept away the plethora of particles and replaced them with a simple underlying structure. That structure encompassed all that we had found, and it predicted things not yet seen. They were seen, and the quark model became practical knowledge. Why there were so many states was replaced with how they came to be. A timelier example might be inflation. It is only slightly older than string theory and, when created, was theological speculation, as is often the case with new ideas until someone devises a test. Inflation was attractive because if it were true it would, among other things, solve the problem of the smallness of the temperature fluctuations of the cosmic microwave background radiation. Inflation was not testable at first, but later a test was devised that predicted the size and position of the high angular harmonic peaks in the cosmic microwave background radiation. When those were found, inflation moved from being theological speculation to a kind of intermediate state in which all that is missing to make it practical knowledge is a mathematically sound microscopic realization. The general trend of the path to understanding has been reductionist. We explain our world in terms of a generally decreasing number of assumptions, equations, and constants, although sometimes things have gotten more complicated before they became simpler. Aristotle would have recognized only what he called the property of heaviness and we call gravity. As more was learned, new forces had to be absorbed—first magnetic, then electric. Then we realized that the magnetic and electric forces were really the electromagnetic force. The discovery of radioactivity and the nucleus required the addition of the weak and strong interactions. Grand unified theories have pulled the number back down again. Still, the general direction is always toward the reductionist—understanding complexity in terms of an underlying simplicity. The last big advance in model building came a bit more than 30 years ago with the birth of the standard model. From the very beginning it, like all its predecessors, was an approximation that was expected to be superseded by a better one that would encompass new phenomena beyond the standard model's energy range of validity. Experiment has found things that are not accounted for in it—neutrino masses and mixing and dark matter, for example. However, the back-and-forth between experiment and theory that led to the standard model ended around 1980. Although many new directions were hypothesized, none turned out to have predicted consequences in the region accessible to experiments. That brings us to where we are today, looking for something new and playing with what appear to me to be empty concepts like naturalness, the anthropic principle, and the landscape. More at: http://www.physicstoday.org/vol-59/iss-10/p8.html 
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#2
10-08-2006, 03:12 PM
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Hey Bot,
Some reading I have done in more or less popular literature on hyperspace and such leads to me understand that mathematicians can prove, or demonstrate the existance of more then the 3 or 4 dimensions we experience. Something about some extremely complex equations explaining behaviors in our universe become very simple in 5 or 6 dimensions. Can you explain it any simpler than the books i read? How many dimensions really might exist? Can you even imagine how to think what 5 or 6 or more dimension might be like? I admit it; I am a creaure in 3 or 4 dimensions ( time may, or may not be the 4th). I can imagine a 2 dimensional world ( stick figures on a sheet of paper) but I can't even imagine more than I have experienced. If you are going to post a non-political thread, lets make it a doosey.
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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags 
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#3
10-08-2006, 03:34 PM
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I read the section posted, but not the whole piece yet, but I need to. It seems to me that he is pointing to an inherent problem as theory gets more and more universal, general and abstract. If the theory is correct and explains all events then the theory will not in fact be falsifiable because all events will verify it. This is precisely the problem he seems to find in theology and to a large degree he is correct, but not completely. If theology responds with a modification to its theory in order to accomodate problems that have been raised in testing the theory, then theology is doing a very similar thing to what physicists do. The reason that the problem is more apparent in theology is that concepts of God are always universal with all encompassing implications, whereas in physics, hypotheses often deal with very specific events and explanations and aren't attempting to generate a grand universal theory. When physics does turn to universal grand theory there isn't a sharp line of demarcation between physics and theology. The sharp line of demarcation is largely sociological and cultural, not theoretical. The line is made because theologians are often just interested in preserving a tradition and physicists are often just interested in revising traditions. The best example I can think of in a modern thinker who blurred the distinction is A. N. Whitehead
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1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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#4
10-08-2006, 03:36 PM
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#5
10-08-2006, 03:37 PM
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For a long time I've had similar feelings about the frontiers of quantum physics and cosmology. I have no college education so cannot comment on the mathamatics involved but I think that it is so advanced that it has long superceded the ability of spoken languages to translate it into concepts of which the great unwashed can achieve a meaningful understanding.
This is something I've often discussed with an old high school friend of mine who is now a professor of astrophysics at UCLA. Himself very much a theorist. I wonder if in fact much of the most advanced theories are inherently understandable outside of pure mathamatics. If not, then how does one differentiate them from the morass of metaphysical philosophy? - Peter.
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2021 Chevrolet Spark Formerly... 2000 GMC Sonoma 1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021  2002 Kia Rio. Worst crap on four wheels 1981 240D 4spd stick. 389000 miles. 1984 123 200 1979 116 280S 1972 Cadillac Sedan DeVille 1971 108 280S
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#6
10-08-2006, 03:46 PM
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Quote:
Last edited by GermanStar; 10-08-2006 at 04:04 PM.
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#7
10-08-2006, 03:55 PM
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Anyway, here's the section of that essay that concerns itself with String Theory, to which I believe you were alluding. Bot ----------------------------------------------- String theory was born roughly 25 years ago, and the landscape concept is the latest twist in its evolution. Although string theory needed 10 dimensions in order to work, the prospect of a unique solution to its equations, one that allowed the unification of gravity and quantum mechanics, was enormously attractive. Regrettably, it was not to be. Solutions expanded as it was realized that string theory had more than one variant and expanded still further when it was also realized that as 3-dimensional space can support membranes as well as lines, 10-dimensional space can support multidimensional objects (branes) as well as strings. Today, there seems to be nearly an infinity of solutions, each with different values of fundamental parameters, and no relations among them. The ensemble of all these universes is known as the landscape. No solution that looks like our universe has been found. No correlations have been found such as, for example, if all solutions in the landscape that had a weak coupling anywhere near ours also had a small cosmological constant. What we have is a large number of very good people trying to make something more than philosophy out of string theory. Some, perhaps most, of the attempts do not contribute even if they are formally correct. I still read theory papers and I even understand some of them. One I found particularly relevant is by Stephen Hawking and Thomas Hertog. Their recent paper "Populating the Landscape: A Top-down Approach" starts with what they call a "no boundary" approach that ab initio allows all possible solutions.3 They then want to impose boundary conditions at late times that allow our universe with our coupling constants, number of noncompact dimensions, and so on. This approach can give solutions that allow predictions at later times, they say. That sounds good, but it sounds to me a lot like the despised fine-tuning. If I have to impose on the landscape our conditions of three large space dimensions, a fine structure constant of 1/137, and so on, to make predictions about the future, there would seem to be no difference between the landscape and effective field theory with a few initial conditions imposed. Although the Hawking and Hertog paper sometimes is obscure to me, the authors seem to say that their approach is only useful if the probability distribution of all possible alternatives in the landscape is strongly peaked around our conditions. I'll buy that. To the landscape gardeners I say: Calculate the probabilities of alternative universes, and if ours does not come out with a large probability while all others with content far from ours come out with negligible probability, you have made no useful contribution to physics. It is not that the landscape model is necessarily wrong, but rather that if a huge number of universes with different properties are possible and equally probable, the landscape can make no real contribution other than a philosophic one. That is metaphysics, not physics. We will soon learn a lot. Over the next decade, new facilities will come on line that will allow accelerator experiments at much higher energies. New non-accelerator experiments will be done on the ground, under the ground, and in space. One can hope for new clues that are less subtle than those we have so far that do not fit the standard model. After all, the Hebrews after their escape from Egypt wandered in the desert for 40 years before finding the promised land. It is only a bit more than 30 since the solidification of the standard model.
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#8
10-08-2006, 04:38 PM
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Last edited by GermanStar; 10-08-2006 at 04:51 PM.
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#9
10-08-2006, 05:08 PM
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__________________
1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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#10
10-08-2006, 05:20 PM
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#11
10-08-2006, 06:09 PM
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One day some mathematician is going to have a solution that states that we do not exist - then, we'll be in real trouble!
Or....maybe not....since there are an infinite number of parallel universes (and these are infinitely "close" to one another), we might not even notice the loss of a few million. Just by thinking of the possibility, I just killed of a few hundred thousand, and the more I think of it, the more go. And now that you have just read this, a few more hundred thousand just dissappeared. This is turning into genocide. 
__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein 09 Jetta TDI 1985 300D
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#12
10-08-2006, 08:11 PM
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I must have missed something in that essay that you folks found. The way I read it the essayist has divided physics theoreticians into two groups, one of which is what he terms, theological" in the sense that they have a sort of faith, rather than experimental observations, that theories will work out. He then proceeds to describe several instances of what he believes are examples of that sort of thinking.
B
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#13
10-08-2006, 08:26 PM
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the "sort of faith", sounds like intuition to me.
Then again... why not use intuition? I would think that (as a theorist/physicist of many years) after a while, you develop some sort of sense if something will work or not; or in the least, if there is the need for further exploration. I bet that many of us use intuition on a daily basis - I know I use it for something as simple as predicting what highway lane will be most advantageous. Often times I have to use it to figure out the intent of a post here in the forum. So.. yea...let them use intuition....betcha they are alot better at it than most of us. (As long as they don't think us out of existance)
__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein 09 Jetta TDI 1985 300D
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#14
10-08-2006, 08:30 PM
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No, we just went off on a brief tangent. The author is undoubtedly correct, and the reason is simple. Our thirst for knowledge has exceeded our ability to acquire it.
The 'landscape' he refers to has M-Theory in the middle, and a half dozen variants of string theory along the periphery of a metaphysical cytoplasmic blob. They overlap and offer bizarre inverse relationships with each other. The idea is that each theory is correct from it's particular perspective, but that we presently lack the additional perspectives required to piece them together into a cohesive truth. The fact that this is undoubtedly wishful thinking doesn't automatically disqualify it, especially since nothing more attractive has come along. In the meantime, I have no doubt that important advancements have come from string theory, whether it ultimately pans out or not. At the very least, string theory and its variants will prove wildly useful tangents that may one day lead us to the desperately sought after GUT.
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#15
10-08-2006, 08:40 PM
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I saw a program once on String and M-theory. It takes a while before you can wrap your mind around it. If anything, it makes you realize how small and insignificant you could be.
It also makes me postulate that all those theories are merely puzzle pieces to a big picture (if you will), and I wonder if we as humans are actually equipped enough to wrap our minds around it. I'm thinking that the more removed it is from the dimensions that we are a part of/are familiar with, the more difficult it is to completely understand (grok) those dimensions.
__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein 09 Jetta TDI 1985 300D
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