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Have there been any recent developments in the attempt to unify the standard model of quantum theory with General Relativity? It appears the no progress has been made recently in string theory or loop quantum gravity.
What will make you a pessimist?mathman said:I am somewhat more optimistic. Godel was dealing in mathematics. I doubt if you can "prove" incompleteness for physical theories.
This seems like a total non sequitur to me. How do you get from true but not provable propositions in an axiomatic system to propositions that “won’t make sense”?MathematicalPhysicist said:Well a physical theory is constructed with maths, so the mathematics will be incomplete, and the physics won't make sense anyway, it's either inconsistent or incomplete.
Well "making sense" is with regards to classical logic.Nugatory said:This seems like a total non sequitur to me. How do you get from true but not provable propositions in an axiomatic system to propositions that “won’t make sense”?
Godel does not have "true but not provable" propositions. It has unprovable propositions that become axioms as you extend the maths. The axioms are neither true not false. You can accept them as true, or you can accept various negations of them as true. E.g. the unprovable generalized continuum hypothesis may be accepted or rejected according to taste.Nugatory said:This seems like a total non sequitur to me. How do you get from true but not provable propositions in an axiomatic system to propositions that “won’t make sense”?
It could be something like the Bell theorem for local hidden variables in quantum mechanics. The theorem might state that no theory can simultaneously have properties of being (i) quantum, (ii) general covariant and (iii) obeying some additional property that currently everybody takes for granted.mathman said:I am somewhat more optimistic. Godel was dealing in mathematics. I doubt if you can "prove" incompleteness for physical theories.
Currently, there is no complete and universally accepted theory that unifies quantum theory with General Relativity. While there have been many attempts and theories proposed, none have been able to fully explain the behavior of the universe at both the quantum and macroscopic levels.
One of the main challenges is the fundamental differences between the two theories. Quantum theory describes the behavior of subatomic particles and their interactions, while General Relativity explains the behavior of gravity and the large-scale structure of the universe. These two theories have different mathematical frameworks and are difficult to reconcile.
Scientists use various approaches such as string theory, loop quantum gravity, and quantum field theory in curved spacetime to try and bridge the gap between quantum theory and General Relativity. These theories attempt to explain the behavior of the universe at both the quantum and macroscopic levels.
If a unified theory is achieved, it could lead to a deeper understanding of the fundamental laws of the universe and potentially solve many long-standing mysteries, such as the nature of black holes and the origin of the universe. It could also have practical applications in fields such as quantum computing and space travel.
Yes, there are ongoing experiments and observations in areas such as high-energy physics, cosmology, and gravitational waves that could provide valuable insights and data for the development of a unified theory. These experiments aim to test the predictions of various theories and potentially lead to new discoveries and advancements in our understanding of the universe.