Determinism, Free Will and Paradox

[Mudhammam]

By deterministic I mean that the state of the universe follows uniquely from its state immediately preceeding it. If only probabilities of events are uniquely determined by what came before, but the individual outcome is not, the world is not deterministic in this sense. I'd find it perverse to call such a universe deterministic...

I'm trying to make sense of that with what Greene writes on pg. 341 of "The Elegant Universe"; perhaps you can help clarify. He writes: "The downfall of Laplace's vision, however, does not leave the concept of determinism in total ruins. Wave functions--the probability waves of quantum mechanics--evolve in time according to precise mathematical rules, such as the Schrödinger equation (or its more precise relativistic counterparts, such as the Dirac equation and the Klein-Gordon equation). This informs us that quantum determinism replaces Laplace's classical determinism: Knowledge of the wave functions of all of the fundamental ingredients of the universe at some moment in time allows a 'vast enough' intelligence to determine the wave functions at any prior or future time. Quantum determinism tells us that the probability that any particular event will occur at some chosen time in the future is fully determined by knowledge of the wave functions at any prior time. The probabilistic aspect of quantum mechanics significantly softens Laplacian determinism by shifting inevitability from outcomes to outcome-likelihoods, but the latter are fully determined within the conventional framework of quantum theory."

Perhaps he's simply more lax in his usage of "determinism" than you are?

[Exian]

I can choose to eat a Mars Bar, or to rape an entire nation, or to type in an internet forum, or to sit next to a river for 20 years, and in the end it all "works out," because the paradox of determinism means that everything I do is exactly what I am meant to do in order to keep the Universe chugging along toward the Big Crunch (or whatever).

Are you saying that- because the end is unavoidable and immutable, everything we do is towards that end, no matter the choices we make, and so we have free will but the end is determined?

[Alex K]

Commenting on Greene's text, I don't think he's saying anything particularly complicated - we can in principle say something about the probability of arbitrary future events if we know the wave function of the universe at any given moment in time exactly. This may be called quantum determinism, but it's a very weak thing, don't you think.

What I notice is that he likes to assigns a degree of realism to the wave function (as something which is real, one could in principle know, and which persists indefinitely, is all- encompassing, only governed by the schroedinger equation). This, to me, is already very close to a full many worlds interpretation. In fact, I think it is the MWI with him not admitying it.Others would not go as far as he does here.

[Mudhammam]

Commenting on Greene's text, I don't think he's saying anything particularly complicated - we can in principle say something about the probability of arbitrary future events if we know the wave function of the universe at any given moment in time exactly. This may be called quantum determinism, but it's a very weak thing, don't you think.

What I notice is that he likes to assigns a degree of realism to the wave function (as something which is real, one could in principle know, and which persists indefinitely, is all- encompassing, only governed by the schroedinger equation). This, to me, is already very close to a full many worlds interpretation. In fact, I think it is the MWI with him not admitying it.Others would not go as far as he does here.

Yeah, I would agree, it's a "weak" determinism in comparison to macroscopic causality. So, to what extent do the probabilistic outcomes of wave-functions affect anything in our lives or the Universe at large, other than the implication that when the Universe was really really really small and really really really young, "all bets were off" with regards to the forms that matter would eventually take?

[The Grand Nudger]

-and that's the (or one of the) hook for why things seem so different in a QM experiment than they do in our lives as we experience them, or the universe as we experience -it-. If you isolate something, and find that a great deal is possible - that's not entirely surprising. Once you have forces pushing in from every direction, and a mountain of the same behind you....many of those possibilities that a QM particle might be able to realize in isolation become a non-issue as a part in the whole mess of interaction at a massively grander scale.

To put it another way, the more modifiers you add, the smaller the range of probability becomes. Perhaps x can be whatever it wants, it's truly random. However, when x interacts with y, lets say (just for ease of use) that half of those possibilities are removed. Add a z, take away another half. So forth and so on for everything that's interacting with any other thing....and up here...there's a whole hell of alot of "things".

[Mudhammam]

-and that's the (or one of the) hook for why things seem so different in a QM experiment than they do in our lives as we experience them, or the universe as we experience -it-. If you isolate something, and find that a great deal is possible - that's not entirely surprising. Once you have forces pushing in from every direction, and a mountain of the same behind you....many of those possibilities that a QM particle might be able to realize in isolation become a non-issue as a part in the whole mess of interaction at a massively grander scale.

To put it another way, the more modifiers you add, the smaller the range of probability becomes. Perhaps x can be whatever it wants, it's truly random. However, when x interacts with y, lets say (just for ease of use) that half of those possibilities are removed. Add a z, take away another half. So forth and so on for everything that's interacting with any other thing....and up here...there's a whole hell of alot of "things".

So, the indeterminacy met on QM is for the most part negligible, and in specific instances where it is relevant, these are far removed from any environment likely to include a multitude of modifiers... which I would presume is the case with most objects larger than the atom?

[The Grand Nudger]

That's one explanation. Whether or not it's -the- explanation is beyond me. Would certainly seem to be in line with our experience, but since our experience is precisely the issue of contention......lol....

(if i could figure out my keyboard or paste my hdl into the forums I could express this as an algorithm)

[Davka]

the ability to act in non-predictable ways.

By which I mean that a theoretical infinitely-powerful computer, given full and accurate knowledge of the entire Universe and the ability to predict any future event based on total knowledge of all past events would still not be able to predict your actions.

Hm, I don't find that entirely satisfactory, but if we run with it, determinism automatically precludes free will, and lack of determinism produces it. It becomes almost the same thing.

Not at all - in fact, it's almost the opposite.

Given a purely deterministic Universe, free will would be defined as the ability of an individual to act in non-deterministic ways. Determinism would preclude free will only up until the point at which the composition of individual life forms (specifically the brain) reaches sufficient complexity as to generate the emergent property of free will. IOW, determinism in a sufficiently complex Universe would necessarily generate "pockets" of free will.

Look (for example) at the way in which the Solar System - most notably in the Earth-Moon-Sun part of the system - generates pockets of "reverse entropy," in which the energy from the Sun is allowing order and complexity to increase on Earth, at least for a little while.

We can argue that this "reverse entropy" is illusory in the larger scheme of things, representing really nothing more than minor side-effects of energy exchange between the Earth and the Sun, yet it cannot be denied that life on Earth has been increasing in complexity and order for billions of years. Thus, although entropy cannot truly be reversed, there exist little pockets - eddies in the inevitable flow towards Universal heat death - which temporarily (albeit futilely) allow for a bit of 'swimming upstream.'

Similarly, in a deterministic Universe, there might emerge pockets of non-deterministic behavior: unpredictable bubbles within the predictable whole. Free Will on the micro scale, if you will.

I'm tellin' ya, word salad FTW every time!

[The Grand Nudger]

enclaves are not an expression of the negation of entropy..they're still a function -of it-. All of the stuff in the sun came from elsewhere, it all washes. No "reverse entropy" is being "generated"..it's just happening more slowly in one place at the expense of an increase in another.

[Davka]

enclaves are not an expression of the negation of entropy..they're still a function -of it-. All of the stuff in the sun came from elsewhere, it all washes. No "reverse entropy" is being "generated"..it's just happening more slowly in one place at the expense of an increase in another.

"More slowly" can also be expressed as "in reverse" - it's relative, nu?

Certainly these enclaves are a function of entropy, I intended to make that clear in my post (and apparently failed). My argument is that "free will" could be a similar sort of pocket or enclave in a deterministic universe. Just as there are small areas in an entropic system in which complexity is increasing temporarily, so there might be small areas in a deterministic system in which determinism/predictability is temporarily missing.