String Theory Does Not Win a Nobel, and I Win a Long Bet

Post by wuliwong » Thu, Oct 10, 2019, 4:24 PM UTC

selectionbias wrote: post #100

wuliwong wrote: post #54

Earlier quoted context omitted.

>a lot of people also think there is a "true" theory that will perfectly explain how the universe evolves Doesn't Godel's incompleteness theorems make this doubtful? Logic was not my area of focus but I thought the basic idea was that there is always going to be some un-answerable question(s) or un-provable answers in any consistent theory[1]? I'm pretty sure there is not significant work using non-axiomatic math, I'…

In the context of the incompleteness theorem a 'theory' consists of a formal language to describe theorems, some primitive axioms and some rules that can be used to prove theorems from the axioms. Godel's incompleteness theorem states (loosely speaking) that if a theory is rich enough to describe the arithmetic of the natural numbers, is consistent and is 'effectively axiomatized', then there are statements that can…

Post by beastoven » Thu, Oct 10, 2019, 4:51 PM UTC

drdeca wrote: post #117

wuliwong wrote: post #54

Earlier quoted context omitted.

>a lot of people also think there is a "true" theory that will perfectly explain how the universe evolves Doesn't Godel's incompleteness theorems make this doubtful? Logic was not my area of focus but I thought the basic idea was that there is always going to be some un-answerable question(s) or un-provable answers in any consistent theory[1]? I'm pretty sure there is not significant work using non-axiomatic math, I'…

Presburger arithmetic is a decidable theory. "This means it is possible to algorithmically determine, for any sentence in the language of Presburger arithmetic, whether that sentence is provable from the axioms of Presburger arithmetic." If you don't understand what the incompleteness theorems say, be wary of citing them.

Post by thanatropism » Thu, Oct 10, 2019, 5:19 PM UTC

Animats wrote: post #154

thanatropism wrote: post #96

Earlier quoted context omitted.

You're being downvoted, but we' re basically drunk on these amazing successes in Computer Vision and apply at least some magical thinking when expecting them to extend to general (e.g. reinforcement learning) domains.

AI is doing a lot better now than in the 1980s. AI back then was groups at MIT, Stanford, and CMU, and a few small groups elsewhere. Almost all the 1980s AI startups went bust. This time, there's enough success that the field is self-funding. Cynically, because mediocre machine learning is good enough for ad targeting.

Post by max_zhou » Thu, Oct 10, 2019, 8:03 PM UTC

sanxiyn wrote: post #105

max_zhou wrote: post #50

Correct me if I am wrong. i think string theory is searched not just because of its beauty, but also because of existing problems in general relativity. For example, the center of black hole is predicted to be `infinite` in terms of many metrics . But the center is also part of the spacetime, it should bear some measurable values. The answer might require quantum physics since it is microscopic. Therefore, the unifyi…

Yes, quantum gravity is searched for. String theory is not quantum gravity, it is a specific approach to quantum gravity that has not been very fruitful.

Post by FiatLuxDave » Thu, Oct 10, 2019, 8:57 PM UTC

gimboland wrote: post #123

JohnJamesRambo wrote: post #115

Earlier quoted context omitted.

Well I’m not reading Feynman’s take because he is dead right now.

I like the "right now" there. Like, fingers crossed, that could change...