String Theory
Jan. 8th, 2007 06:46 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
jmatonakI have a lot of contempt for string theory.
Let me get some things off my chest: many string theorists, including all of the principal ones, are better mathematicians than I am, and also better physicists. Although I came to my objections on my own, they were originally put forward by eminent physicists of a prior generation. Consequently, this all smacks of hatin'. Furthermore, I had a lot of contempt for the string theorists I knew when I was in school- more hatin'- but that was primarily because of the kind of people they were and not the nature of their work.
String theory is a complicated mathematical scheme that is largely experimentally untestable. In fact, many stringies look upon that as a virtue. A properly-constructed string theory can be pushed into arbitrarily close agreement with known physics, and has a wide degree of adjustability to suit ambiguities and new discoveries. Its principal virtue is mathematical elegance and complexity.
Ptolemaic explanations of the solar system took as a given that the planets (and the Sun) revolved around the Earth. Another given was that celestial objects travelled in circles. To account for discrepancies between observations and the celestial behavior suggested by the model, theorists added "epicycles"- circular flourishes the planets periodically allowed themselves as they travelled along their major, circular paths around the Earth. At its mature stage of development, the Ptolemaic theory agreed completely with the known results of observation. An elaborate, adjustable system was built from first principles- that the planets move in (a) circular orbits around (b) the Earth.
Modern observations, along with actually, you know, sending things into space, has confirmed that the planets travel in ellipses around the sun, and that, in fact, the Earth does this too. So... the Ptolemaic cosmology is ingenious bullshit.
But, of course, modern smart people could never bullshit themselves like that. Not in physics. Because modern physicists, unlike modern international-relations experts, modern physicians, and modern economists, not to mention every other type of modern scientist or intellectual worker, are just too smart.
I love mathematically elegant things. But if mathematical elegance implied physical reality, physical constants would be expressed in rounder numbers. :p
Let me get some things off my chest: many string theorists, including all of the principal ones, are better mathematicians than I am, and also better physicists. Although I came to my objections on my own, they were originally put forward by eminent physicists of a prior generation. Consequently, this all smacks of hatin'. Furthermore, I had a lot of contempt for the string theorists I knew when I was in school- more hatin'- but that was primarily because of the kind of people they were and not the nature of their work.
String theory is a complicated mathematical scheme that is largely experimentally untestable. In fact, many stringies look upon that as a virtue. A properly-constructed string theory can be pushed into arbitrarily close agreement with known physics, and has a wide degree of adjustability to suit ambiguities and new discoveries. Its principal virtue is mathematical elegance and complexity.
Ptolemaic explanations of the solar system took as a given that the planets (and the Sun) revolved around the Earth. Another given was that celestial objects travelled in circles. To account for discrepancies between observations and the celestial behavior suggested by the model, theorists added "epicycles"- circular flourishes the planets periodically allowed themselves as they travelled along their major, circular paths around the Earth. At its mature stage of development, the Ptolemaic theory agreed completely with the known results of observation. An elaborate, adjustable system was built from first principles- that the planets move in (a) circular orbits around (b) the Earth.
Modern observations, along with actually, you know, sending things into space, has confirmed that the planets travel in ellipses around the sun, and that, in fact, the Earth does this too. So... the Ptolemaic cosmology is ingenious bullshit.
But, of course, modern smart people could never bullshit themselves like that. Not in physics. Because modern physicists, unlike modern international-relations experts, modern physicians, and modern economists, not to mention every other type of modern scientist or intellectual worker, are just too smart.
I love mathematically elegant things. But if mathematical elegance implied physical reality, physical constants would be expressed in rounder numbers. :p
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no subject
Date: 2007-01-08 04:55 pm (UTC)Plutoed
Verb. to pluto someone or something is to downgrade, demote or remove altogether from a prestigious group or list, like what was done to the planet of the same name.
"He was plutoed like an old pair of shoes."
And I think there is a certain amount of mathematical elegance in nature. I'm very fond of pi and e, irrational as they may be.
no subject
Date: 2007-01-08 05:07 pm (UTC)String theory doesn't explain values of important physical constants. If it did, those numbers would have the elegant definition of pi and e. Instead, string theories- and there are many- take those numbers as inputs. The mathematics is designed to accept observations like the mass of the proton, but not to explain them or constrain them in any way. No matter the observation, the math can be Ptolemaically augmented to account for it.
Is it possible that there are many, many potential universes and we just happen to live in the one with these parameters? Sure. But string theory does *nothing* to explain why this should be so. It's a complicated piece of math that really has no more business calling itself "physics" than does the theory of finite groups.
(It isn't really even that beautiful. It's like a big house made out of popsicle sticks- kind of an achievement but also a little eccentric and nuts.)
Of course, I'm sure that Brian Greene gets more dates because of The Elegant Universe than I've gotten, ever. At least Sheldon Glashow agrees with me.
no subject
Date: 2007-01-08 09:03 pm (UTC)I was just disagreeing with "if mathematical elegance implied physical reality, physical constants would be expressed in rounder numbers." .. and making a joke about irrational numbers. :p
no subject
Date: 2007-01-09 05:35 am (UTC)I've barely delved into the theory itself. The math is beyond me. I've heard that it's a beautiful theory, and I'm sure it is. But until it can be physically demonstrated, it's not worth much. We see evidence of the big bang theory in the cosmic microwave background radiation. Where's evidence of string theory? It's been suggested that small discrepancies in this radiation that appear when it is mapped out across the sky are the result of quantum perturbations in the very early universe that seeded instabilities that grew into these deviations. The result of strings, maybe? I don't know. But at the moment, the problem with strings is that their size makes them completely undetectable in any capacity. If they're going to be detected, it will only be by their actions on larger objects/systems.
I don't think string theory is necessarily a dead end, but I have to admit that I get impatient with the idea that it represents The Final Theory of Everything that physicists want so badly to find. Beautiful math aside, until there's physical proof, it's just a pretty idea.
no subject
Date: 2007-01-09 09:48 am (UTC)Yeah!
I have *nothing* against pretty ideas. I can even sometimes accept that when you have two competing ideas, the pretty one is more likely to be right because mathematical prettiness involves a kind of parsimony and physical systems are often parsimonious. But without *something* to anchor your pretty ideas to, how do you know you're describing anything that exists outside your own head?