How important is a ToE?

[Daecon]

From my limited understanding, a Theory of Everything would seek to unite both quantum physics and general relativity in one overall framework?

How important is it that these two be connected? 

Could they not be two completely and separate things that together create the universe, instead of being two aspects of the same thing? 

I'm sure there's a better way I can word this, but hopefully you get the gist of what I mean?

[YaDinghus]

1 hour ago, Daecon said:

How important is it that these two be connected? 

Could they not be two completely and separate things that together create the universe, instead of being two aspects of the same thing? 

Considering how powerful both theories are and how accurately they describe the universe at their scale, a ToE would be amazing. They are however not things that created the universe, they are theories.

A theory that encompasses both quantum physics and GR would not only better describe how the universe came to be, it would also better describe the universe we are living in as it is now and how it evolves in the future. Is that a ToE? I don't know. I personally believe that there is an infinite amount of knowledge in the universe which can't be discovered in the limited, albeit very long time the Universe will be habitable (https://en.m.wikipedia.org/wiki/Heat_death_of_the_universe), which would mean there can't really be a theory of everything. But that doesn't mean we should stop trying to find out.

[StringJunky]

They emerged together, so they must be mathematically entwined somehow.

[studiot]

Good question, +1

Personally I don't care whether there is a TOE, any more than I care what clothes you are wearing or if there is a God.

I can see the past justification for compact notation and formulae, when paper was scarce and it took significant effort to put writing and images onto it.

But, as any Engineer knows, if you have a compact notation for 9 equations and you want to calculate the size and other properties of something,

Sure you can write down a compact equation containing it all, but as soon as you want actual numbers to work with you have to write down and work out all 9 equations.

There is no short cut.

[geordief]

Reminds me a bit of an old thread of mine  I was looking at yesterday

 

https://www.scienceforums.net/topic/107248-quantum-gravity/

I was wondering then  whether  the macro side of things might  be explained purely as a statistical outcome.

 

I was thinking along those lines perhaps as a result of very recently learning that computer translations may have  have dispensed with the rules of language and simply depend on statistical correlations to produce the results they do (there was a prog about statistics on BBC4)

 

[koti]

I’m not convinved that the unification whether it will be some version of string theory or some other version of quantum gravity, has to be necessarily the „theory of everything”

Edited June 3, 2018 by koti

[swansont]

57 minutes ago, koti said:

I’m not convinved that the unification whether it will be some version of string theory or some other version of quantum gravity, has to be necessarily the „theory of everything”

I think it wouldn't be. It would be a quantum theory of gravity, which leaves out a whole bunch of stuff.

7 hours ago, Daecon said:

From my limited understanding, a Theory of Everything would seek to unite both quantum physics and general relativity in one overall framework?

That would be one part of a ToE.

Quote

How important is it that these two be connected? 

If you want to describe what's happening in very strong gravity and/or on very small scales, it's crucial.

Quote

Could they not be two completely and separate things that together create the universe, instead of being two aspects of the same thing? 

No. GR fails to work on the scales where a quantum theory is needed. i.e. it gives the wrong answer. Much like classical mechanics gives the wrong answer at small scales, e.g. what's going on in the atom.

[StringJunky]

3 minutes ago, swansont said:

No. GR fails to work on the scales where a quantum theory is needed.

I think he means GR describing the big stuff and QT describing the small stuff and they meet somewhere or overlap. Essentially, they are exclusive to their respective domain as a matter of nature and not as limit of human knowledge..

[Janus]

3 hours ago, StringJunky said:

I think he means GR describing the big stuff and QT describing the small stuff and they meet somewhere or overlap. Essentially, they are exclusive to their respective domain as a matter of nature and not as limit of human knowledge..

But the point that swansont is making is that GR does make predictions as to what should happen at the really small scales which does not match what really happens, and there is nothing in the theory itself that says that it only will work until you get down to a certain scale.  This in of itself makes GR an incomplete theory.    It's not enough to just say "the Theory stops working here".    

[StringJunky]

31 minutes ago, Janus said:

But the point that swansont is making is that GR does make predictions as to what should happen at the really small scales which does not match what really happens, and there is nothing in the theory itself that says that it only will work until you get down to a certain scale.  This in of itself makes GR an incomplete theory.    It's not enough to just say "the Theory stops working here".    

OK.

[beecee]

2 hours ago, Janus said:

But the point that swansont is making is that GR does make predictions as to what should happen at the really small scales which does not match what really happens, and there is nothing in the theory itself that says that it only will work until you get down to a certain scale.  This in of itself makes GR an incomplete theory.    It's not enough to just say "the Theory stops working here".    

Much like using a rule or measuring tape when  turning down a cylinder and/or piston, instead of a Vernier caliper or micrometer? 

[geordief]

3 hours ago, Janus said:

But the point that swansont is making is that GR does make predictions as to what should happen at the really small scales which does not match what really happens, and there is nothing in the theory itself that says that it only will work until you get down to a certain scale.  This in of itself makes GR an incomplete theory.    It's not enough to just say "the Theory stops working here".    

Nicely said.