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String Theory Put to the Test
secretsather writes to mention that scientists have come up with a definitive test that could prove or disprove string theory. The project is described as "Similar to the well known U.S. particle collider at Fermi Lab, the Large Hadron Collider, scheduled for November 2007, is expected to be the largest, and highest energy particle accelerator in existence; it will use liquid helium cooled superconducting magnets to produce electric fields that will propel particles to near light speeds in a 16.7 mile circular tunnel. They then introduce a new particle into the accelerator, which collides with the existing ones, scattering many other mysterious subatomic particles about."
I'm by no means an expert in string theory. I barely grasp the basic concepts. However I am an engineer who has taken a LOT of physics classes over the years and I'm not completely ignorant either.
String theory has always struck me as a modern day version of epicycles before it was realized that planets follow ellipses instead of circles. It just seems like we're trying to fit the math to the model instead of modifying the model so that the math makes sense. Add in the fact that it makes no testable predictions (not yet anyway) and it's bordering on not being science anymore. Maybe technology advances will change that but then again maybe not.
Maybe string theory is right, I don't honestly know. But it seems like a lot of group think is going on and little progress is being made.
I wouldn't call that junk science so much as failure to make a pedantic distinction.
If experiment can show that string theory makes predictions more accurately than current models, I'd say that proven is a good enough word to describe what has happened. Not in the sense that it's been shown to be an absolutely correct description of the machinations of the universe. Proven in the way that General Relativity was proven - decades before all of its predictions had been tested. Proven as in "it's been shown to be a better model," i.e., proven in about the same sense a person can "prove himself."
I don't think it's whining. The public's confusion about science surely stems in part from sloppy reporting.
How often have we heard someone claim that we shouldn't allow something because it has never been proven to be safe? Such comments show serious misunderstanding about the nature of knowledge.
From the wording in the article it sounds like they actually want string theory to fail. . .
.despite the fact that we have few alternatives so far.
A test in which a theory fails is the most useful sort of test.
. .
I cannot accept a theory simply because I don't know what to replace it with. Make the tests, generate failures; and then new theories which take the failures into account. That's how the alternatives come into being in the first place. That's why the "failures" are the most useful.
"Successes" only make us complacent with the state of our knowledge, which might well be wrong anyway. "Failures" let us know where we lack knowledge. Science is not done where we know, but where "here there be dragons." It's about exploring the dark corners of the map, not sitting in our offices diddling with ourselves.
We leave that sort of thing to the engineers.
And think about this:
Who says we need an alternative? The quest for a Unified Field Theory is an asthetic desire on the part of physicists. The universe is well known for taking our asthetic desires and shoving them up our collective arses.
Perhaps there can be only two.
KFG
Not so fast -- for a start, you'd need all data from the universe's future, too. But even then, you still won't have proved your theory, unless you count all possible parallel universes too. Even if every event in the history of the universe fails to falsify a theory, it is still possible that you just got lucky, and nothing ever happened in such a way as to disprove the theory. Of course, I'll concede that in that situation, you've got a pretty useful theory and the errors it contains are moot for someone living in the universe in question.
String theory has one particle - the string. It has one force which emerges from the very simple dynamics put into it at the outset. A wide spectrum of particles and interactions emerges from it in a natural way. There is little choice for the dimension of spacetime - the theory locks it down from the beginning. Gravity emerges from it naturally - something that doesn't even get mentioned in the standard model. There are close to zero arbitrary constants. And at bottom, the initial assumptions of String Theory are really simple. Simpler than other quantum field theories.
The problem with String Theory is that taken at surface value it doesn't match the universe we see. We don't see a 10-dimensional universe, we don't see the predicted spectrum of particles and so on. The publicised problems we see with String theory are from all the attempts to make our 4D universe emerge from it - and the incredible freedom we have in doing so (eg. by folding up dimensions in various ways). At core, String theory is simple, beautiful and as far from arbitrary as you can imagine. There are all kinds of things wrong with String theory. But they have nothing to do with "adding as many dimensions and undefinable, physically meaningless constants as possible", which sounds more like the ramblings of someone who doesn't have a clue what String Theory is about.
Note that I am neither for nor against String Theory, which makes me part of a tiny minority in the physics world. I certainly doubt it's the ultimate theory of anything, but I also think that there is a lot of uninformed criticism of it. I'm just telling it like it is without my own ax to grind.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
THE EARTH REVOLVES AROUND THE SUN?? You must be joking. I can clearly see the sun rising and setting. Any theory that interferes with the perceptions that I am comfortable with, is obviously bollocks. Last time I checked I couldn't see any evidence for the earth revolving around the sun, even when looking under the sofa.
Censorship is telling a man he can't have a steak just because a baby can't chew it. --Mark Twain
As I always like to point out, the most important thing to remember about Occam's Razor is that it's a rule of thumb, not a Law of Nature. If two proposed theories otherwise seem to work similarly well, but one introduces fewer assumptions than the other, Occam's Razor suggests that the former is probably better than the latter, but you can't take this as "proof" -- at best, it lets you make a better educated guess about which avenue is likely to be more fruitful to continue exploring.
David Gould
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