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Has he predicted anything that has ever been observed? Because in my layperson's eyes that's the difference between math and theoretical physics.

whatshisface 3y ago
Predicting a truly novel observation is rare, and has always been rare. Mostly what physicists do is clarify our understanding of things we've already observed, and extend techniques to handle cases that are more difficult to calculate than the cases that are presently considered tractable. For every one coulomb's law or socks-cling-to-stuff-after-drying effect there are a million papers about figuring out how to calculate the electrostatic fields of various configurations. The vast majority of what theoretical physicists do is "just math" except that unlike math, it's aimed at a problem posed by nature rather than a problem imagined up on the basis of what seems most interesting.
- philipov 3y ago
  It's no coincidence that the most important fields of math are well suited to solving physics problems. Looking back through history, so many of the most famous mathematicians were also physicists. Math was invented to solve two kinds of problems: physics and accounting.
nyssos 3y ago
> Because in my layperson's eyes that's the difference between math and theoretical physics. Not really. The distinction, to the extent that there even is one, is mostly a matter of motivation and methodology. Broadly generalizing: mathematical physicists (i.e. mathematicians) are interested in physical theories that seem like they might need interesting new mathematical tools to understand, while theoretical physicists are interested in theories that seem like they might have something to tell us about the true structure of whatever the object of interest is. There are other differences downstream of this, of course: - mathematical physicists are rigorous while theoretical physicists will let it lapse if that gets them physically correct answers - physicists care less about inconsistencies in theories they know are wrong anyway - mathematicians stay long after all the physical content has been mined out (a significant fraction of just-plain-mathematics is the end result of this process) and so on. But you can find people anywhere between these poles. Witten can (and sometimes does) produce world-class mathematics when he wants to, but most of his work is on the physics side of the spectrum.

whatshisface 3y ago

Predicting a truly novel observation is rare, and has always been rare. Mostly what physicists do is clarify our understanding of things we've already observed, and extend techniques to handle cases that are more difficult to calculate than the cases that are presently considered tractable. For every one coulomb's law or socks-cling-to-stuff-after-drying effect there are a million papers about figuring out how to calculate the electrostatic fields of various configurations. The vast majority of what theoretical physicists do is "just math" except that unlike math, it's aimed at a problem posed by nature rather than a problem imagined up on the basis of what seems most interesting.

philipov 3y ago
It's no coincidence that the most important fields of math are well suited to solving physics problems. Looking back through history, so many of the most famous mathematicians were also physicists. Math was invented to solve two kinds of problems: physics and accounting.

nyssos 3y ago

> Because in my layperson's eyes that's the difference between math and theoretical physics. Not really. The distinction, to the extent that there even is one, is mostly a matter of motivation and methodology. Broadly generalizing: mathematical physicists (i.e. mathematicians) are interested in physical theories that seem like they might need interesting new mathematical tools to understand, while theoretical physicists are interested in theories that seem like they might have something to tell us about the true structure of whatever the object of interest is. There are other differences downstream of this, of course: - mathematical physicists are rigorous while theoretical physicists will let it lapse if that gets them physically correct answers - physicists care less about inconsistencies in theories they know are wrong anyway - mathematicians stay long after all the physical content has been mined out (a significant fraction of just-plain-mathematics is the end result of this process) and so on. But you can find people anywhere between these poles. Witten can (and sometimes does) produce world-class mathematics when he wants to, but most of his work is on the physics side of the spectrum.