Theory Denies “Theory of Everything”

[Tharmas]

This article (that I read in Scientific American) claims that fully understanding the universe is beyond the grasp of any individual that could exist within the universe.

I’m wondering if this has implications with regards Determinism and ultimately Free Will.

[Pyrogenesis]

Interesting, but not particularly surprising. Though I don't personally feel that this formal argument makes the case more strongly than the simple fact that as biological organisms of a particular sort, with our particular evolution and cognitive makeup, we will necessarily have to make use of our particular evolved capacities and thus every explanation of whatever must be filtered through this. Pure "objectivity" is a metaphysical ideal, and depicts a fantasy world of observer-less universe, an impossibility.

Also, didn't Russell already solve the liar's paradox by breaking it up into different levels of abstraction? But I forgot the details.

[Jinx]

Originally Posted by Tharmas

I’m wondering if this has implications with regards Determinism and ultimately Free Will.

Probably not much that quantum uncertainty doesn't already imply. He's not saying (according to that article) that the universe isn't governed by deterministic laws, or even that we can't know those deterministic laws:

Originally Posted by Wolpert

Knowing the exact current state of the entire universe, knowing all the laws governing the universe and having unlimited computing power is no help to the demon in saying truthfully what its answer will be.

It sounds like he's just developing a formal proof of an idea that would go something vaguely like 'each fundamental act of understanding a fact constitutes a new fact and thus it's logically impossible to ever have understood the totality of facts'.

[grumpy]

Generally I don't comment on these really sciency threads because as a fully accredited and certified dunce, it doesn't take much for me to get in over my head.

But as I read the article, what I got out of it was that no thinking entity, organic or machine, could possibly fully understand any system more complex than itself.

This seems to me self-evident.

[Gurdur]

Oddly enough, Grumpy hits the nail. The limits of knowledge are a given; to understand the universe completely, one needs a calculating machine at the very least bigger than the universe.

Then there is the premise that in the end the universe is not fully deterministic; which means it can't be calculated anyway. This is of course a fascinating topic (at least for me).

[Fizzle]

Some quantum events are not deterministic, right? I mean, electrons sometimes pop into and out of existence for no reason at all, IIRC

Radioactive decay has no discernible cause either IIRC.

[Don Alhambra]

Originally Posted by Fizzle

Some quantum events are not deterministic, right? I mean, electrons sometimes pop into and out of existence for no reason at all, IIRC

Radioactive decay has no discernible cause either IIRC.

Correct, quantum events are (as far as we can tell) truly random. And radioactive decay is too.

There's a lot of fascinating literature and debate on free will, indeterminacy and the brain... which I am not going to go into again right now.

[Jinx]

Originally Posted by Don Alhambra

Correct, quantum events are (as far as we can tell) truly random. And radioactive decay is too.

I spoke to a particle physicist about this recently, and he seemed to disagree on this - he thought it was an open question, but forced to guess he would opt for determinism.

[Fizzle]

Originally Posted by Don Alhambra

Correct, quantum events are (as far as we can tell) truly random. And radioactive decay is too.

There's a lot of fascinating literature and debate on free will, indeterminacy and the brain... which I am not going to go into again right now.

Feel free...

[Don Alhambra]

Originally Posted by Jinx

I spoke to a particle physicist about this recently, and he seemed to disagree on this - he thought it was an open question, but forced to guess he would opt for determinism.

Well, the whole point of quantum theory is that you don't have a deterministic framework but rather one that is based on probability distributions!

[grumpy]

Oddly enough?

[Jinx]

Originally Posted by Don Alhambra

Well, the whole point of quantum theory is that you don't have a deterministic framework but rather one that is based on probability distributions!

I can hardly argue the point, but that's what he said (unless I completely misunderstood, which is possible...). I'll see if I can get him to clarify next time I speak to him.

From what I know of QT though, I thought the most we could say for certain was that it was impossible for an observer to predict both velocity and location of small particles (and hence reliant on probability distribution from *our* pov)?

[Fizzle]

Originally Posted by Jinx

I can hardly argue the point, but that's what he said (unless I completely misunderstood, which is possible...). I'll see if I can get him to clarify next time I speak to him.

From what I know of QT though, I thought the most we could say for certain was that it was impossible for an observer to predict both velocity and location of small particles (and hence reliant on probability distribution from *our* pov)?

That would be Heisenberg's Uncertainty Principle, due to particle-wave duality (that's the name, right?)


http://en.wikipedia.org/wiki/Uncertainty_principle

[Jinx]

Yes.

[Don Alhambra]

Originally Posted by Jinx

From what I know of QT though, I thought the most we could say for certain was that it was impossible for an observer to predict both velocity and location of small particles (and hence reliant on probability distribution from *our* pov)?

Originally Posted by Fizzle

That would be Heisenberg's Uncertainty Principle, due to particle-wave duality (that's the name, right?)


http://en.wikipedia.org/wiki/Uncertainty_principle

Originally Posted by Jinx

Yes.

Not quite. The uncertainty principle isn't due to wave-particle duality, I don't think. They're both results of the underlying QM principles. Uncertainty just means, as Jinx said, that the position and momentum of a particle cannot ever, in principle, be known - and not just by us. Even bouncing a single photon off a particle to measure its position will change its momentum; there is always an inherent uncertainty.

That's different from the idea of quantum vacuum fluctuations though, in which particles pop in and out of existence at random and almost instantaneously. It's that underlying randomness that's the basis for the non-determinacy of the universe.

[Fizzle]

In quantum mechanics, a particle is described by a wave. The position is where the wave is concentrated and the momentum is the wavelength. The position is uncertain to the degree that the wave is spread out, and the momentum is uncertain to the degree that the wavelength is ill-defined.

The only kind of wave with a definite position is concentrated at one point, and such a wave has an indefinite wavelength. Conversely, the only kind of wave with a definite wavelength is an infinite regular periodic oscillation over all space, which has no definite position. So in quantum mechanics, there are no states that describe a particle with both a definite position and a definite momentum. The more precise the position, the less precise the momentum.

That's from the wiki. I think it says that the principle arises from the duality.

Are you saying particle-wave duality and the UP are basically the same thing, just on different terms (the first, just a description of state the second a description of measuring)?

[dglas]

It seems to me must be careful to distinguish very carefully between reality and our knowledge-states with respect to it. To say we do not or cannot know the causal relationships is not to say there aren't any. Even if we determine (sorry) that we cannot in principle measure in a way that provides correlation, it doesn't mean we have license to make outlandish claims about "free will" or mind/body duality, like so many do.

To go from not knowing the determination chain to "not deterministic" is an unwarranted leap.

[grumpy]

I'm going to risk shitting myself here again, but an earlier success on this thread makes me reckless.

That's different from the idea of quantum vacuum fluctuations though, in which particles pop in and out of existence at random and almost instantaneously. It's that underlying randomness that's the basis for the non-determinacy of the universe.

The above discussion puts me in mind of something I read many years ago about Fred Hoyle's "steady state" universe. He seemed to be saying that in roughly the volume of a modern skyscraper, (which were smaller in those days) about once a year a hydrogen atom would just come into existence, along with a volume of space to contain it. Throughout the universe this would amount to many tons of matter and cubic miles of space per second.

The new space accounted for the red shift of distant galaxies, and that red shift, in turn, allowed him to calculate how much new space was being created.

Or something like that.

Was he half right? He intuited matter springing into existence, but not matter springing out?

[Fizzle]

Well, yes, he was somewhat right. In the sense of something popping into existence for no reason at all, but that's not an original idea, I think.


Also, IIRC, it was an ad hoc explanation for the expanding universe in order to make it fit with Hubble's findings. It was never confirmed and when CMB was discovered and measured, bye bye SST.

[Jinx]

Originally Posted by Don Alhambra

Not quite. The uncertainty principle isn't due to wave-particle duality, I don't think. They're both results of the underlying QM principles. Uncertainty just means, as Jinx said, that the position and momentum of a particle cannot ever, in principle, be known - and not just by us. Even bouncing a single photon off a particle to measure its position will change its momentum; there is always an inherent uncertainty.

Well yeah. By 'our perception' I meant 'the perception of anything larger than a photon'. I probably should have made that clearer

[Tharmas]

Originally Posted by dglas

To go from not knowing the determination chain to "not deterministic" is an unwarranted leap.

Point taken. One would hope it didn’t need to be said.

A question that interests me (and I am frustrated by the vagueness of the article) is can one say that one can in principle determine the causal connections between any two events, assuming a deterministic universe?

It would appear the answer is that one can not.

I wonder, given a system of sufficient complexity that one cannot guarantee a complete “causal mapping” (if that phrase makes sense), how we would clearly distinguish such a system from a random one?

[Quath]

The best way I visualize particles moving is that they move as a wave. However, they interact as a particle. So the Heisenburg uncertainity just says that you can not make a particle act like a particle in how it moves or exists.

The quantum uncertainity means that if you take identical particles, and send them through a filter with a 50% pass, you can not determine ahead of time what they will do except that know that half will be filtered. In other words, there appears that we can not know enough to determine what this particle will do in this filter. There is no hidden information about the particle or the setup that will shed light on will happen.

But this does not mean there is not a universal hidden variable. If you are use to random numbers in a computer, the analogy is that there could be a universal random number seed we do not know that set up what actions will happen.

There is also the idea that the universe is a solved system. In other words, if you could step out of it and "see" everything, it would appear to be a static object. "Now" is just a subjective term from the reference of a slice of this object through a point in time. In other words, from an outside perspective, we "always" exist.

[homo hirsutus]

I'm sorry, but this isn't fair. You guys need to write in english so the rest of us can understand you.

[Fizzle]

Originally Posted by Quath

The best way I visualize particles moving is that they move as a wave. However, they interact as a particle. So the Heisenburg uncertainity just says that you can not make a particle act like a particle in how it moves or exists.

The quantum uncertainity means that if you take identical particles, and send them through a filter with a 50% pass, you can not determine ahead of time what they will do except that know that half will be filtered. In other words, there appears that we can not know enough to determine what this particle will do in this filter. There is no hidden information about the particle or the setup that will shed light on will happen.

But this does not mean there is not a universal hidden variable. If you are use to random numbers in a computer, the analogy is that there could be a universal random number seed we do not know that set up what actions will happen.

There is also the idea that the universe is a solved system. In other words, if you could step out of it and "see" everything, it would appear to be a static object. "Now" is just a subjective term from the reference of a slice of this object through a point in time. In other words, from an outside perspective, we "always" exist.

[Quath]

Sorry. I was playing City of Heroes while also trying to write my comment. So I was tabbing back and forth from the game when there was a rest spot. So it is even more rambling than it should have been.