5 ms·

Is it just me, or does string theory seem like epicycles all over again: if you throw enough center-intersecting circles into the engine, it can emulate just ab

by tabtab 8y ago

Is it just me, or does string theory seem like epicycles all over again: if you throw enough center-intersecting circles into the engine, it can emulate just about any observed movement of objects in the sky; a sort of "circular regression" in the same way that piling up polynomials gives us Polynomial Regression. String theory is like "dimensional regression". Regression is a powerful tool, but is NOT designed to directly "explain" phenomena, only emulate them. Newton et. al. came along and gave us a much simpler model of gravity and the solar system such that we could toss out the messy nested circle models. (We still can't say that Newton's model is fully "right", but it's certainly simpler.)

ivankolev 8y ago
I thought it was actually Kepler that figured it out...
jcranmer 8y ago
Well, string theory is kind of the anti-epicycle. The epicycles in Ptolemaic astronomy were added to make the math conform to reality, but people didn't believe that the planets actually moved in epicyclic motion. Superstring theory started from the opposite standpoint: the Standard Model is math that works out, but the theory is messy, so superstring theory sought to make an "elegant" theory that checked out with the math... and ended up with a theory that is so general it can't really be disproven. The end result is the same, but the paths to get there are completely different.
- whatshisface 8y ago
  String theory was originally exciting because it had a graviton that worked, and to my knowledge it is really the only theory that contains both the standard model and gravity. LQG is not yet at the point of reproducing 3+1 space as far as I know. So, here's my proposal: saying that the earth orbits the sun in a universe where QED also is true isn't proof of string theory, but it does falsify the standard model and so far to my knowledge most of string competition.
  - jcranmer 8y ago
    > but it does falsify the standard model and so far to my knowledge most of string competition. Not really. The Standard Model makes no prediction about gravity; it makes no claim to. Gravity is so weak that it can be ignored almost everywhere where the other forces come into play: the contribution of gravity compared to electrostatic attraction on the atomic order is smaller than 0.01ZWD is to world GDP... for all of human history. The places where you have to worry about gravity and the other forces at the same time are places where we have precisely no ability to make observations that could distinguish between theories.
deleted 8y ago
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by tabtab 8y ago

ivankolev 8y ago

I thought it was actually Kepler that figured it out...

jcranmer 8y ago

Well, string theory is kind of the anti-epicycle. The epicycles in Ptolemaic astronomy were added to make the math conform to reality, but people didn't believe that the planets actually moved in epicyclic motion. Superstring theory started from the opposite standpoint: the Standard Model is math that works out, but the theory is messy, so superstring theory sought to make an "elegant" theory that checked out with the math... and ended up with a theory that is so general it can't really be disproven. The end result is the same, but the paths to get there are completely different.

whatshisface 8y ago
String theory was originally exciting because it had a graviton that worked, and to my knowledge it is really the only theory that contains both the standard model and gravity. LQG is not yet at the point of reproducing 3+1 space as far as I know. So, here's my proposal: saying that the earth orbits the sun in a universe where QED also is true isn't proof of string theory, but it does falsify the standard model and so far to my knowledge most of string competition.
- jcranmer 8y ago
  > but it does falsify the standard model and so far to my knowledge most of string competition. Not really. The Standard Model makes no prediction about gravity; it makes no claim to. Gravity is so weak that it can be ignored almost everywhere where the other forces come into play: the contribution of gravity compared to electrostatic attraction on the atomic order is smaller than 0.01ZWD is to world GDP... for all of human history. The places where you have to worry about gravity and the other forces at the same time are places where we have precisely no ability to make observations that could distinguish between theories.

deleted 8y ago

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