Beating a Dead Horse: Predetermination

[trustno1]

I don't see how any discussion about determinism (on this forum, especially) can avoid talking about free will.

Well, a good gambit toward steering the conversation away from anthropocentric psychologizing and into purely physical causal determinism might be to toss into the OP some kind of exclusionary codicil.  Say, oh, something like: 

...Now, there are two types of predetermination that we could talk about.  One of them is philosophical predetermination.  This one is the one taken up in religious debates:  Are our actions guided by something?  Basically, it's almost always leads into the 'free will' debate.  But we already have a topic on that one that's doing quite well, actually.

I'm much more interested in scientific predetermination...

[Count Iblis]

Thanks for that clarification.

Otherwise, am I generally correct in my use of the uncertainty principle?

Yes. The uncertainty in position times the uncertainty in momentum is greater than or equal to Planck's constant (uh, there might be a factor of 1/2 in there too but I don't recall off the top of my head). If one knew the position exactly (zero uncertainty) then momentum would be a complete unknown.

[Anfauglir]

Quantum mechanics is by definition indeterministic. This means that at a very small scale (the scale of quantum phenomena) the principle of determinism is invalid. Even though this is a very small effect, it definitely is significant. Signals in your brains, for example are transmitted by electrical charge, including electron's. If you look at a specific atom or ion (except for H+ of course), somewhere in your brains, there's no way to say where the electron is. You can only say where the electron is more likely to be found.
Suppose you find out where that particular electron is. Than you still don't have any clue what it's doing, what it's momentum is.
Suppose you find out what that particular electron is doing, what it's momentum is. Than you still don't have any clue where it is.
This is called the uncertainty principle. You can't know both the location and momentum of an electron. It has been proven that quantum mechanics is indeterministic (of course we still need to question whether the theory is correct, but that's another discussion. Fact is that it's the theory most closely resembling reality).

But are they meaning "indeterministic" in the sense I am?  Sure - we can't know enough about those particles to predict what they will do next.  But what does that imply?  Is it saying that they follow particular rules (and we just don't know what they are), or is it saying that they act in a random manner?

One would assume it is the former, since (when we multiply things up), we "know" that electricity works in a particular way.  It never suddenly doesn't work when most of the electrons go that way instead of this - or does it?

[Str82Hell]

Quantum mechanics is by definition indeterministic. This means that at a very small scale (the scale of quantum phenomena) the principle of determinism is invalid. Even though this is a very small effect, it definitely is significant. Signals in your brains, for example are transmitted by electrical charge, including electron's. If you look at a specific atom or ion (except for H+ of course), somewhere in your brains, there's no way to say where the electron is. You can only say where the electron is more likely to be found.
Suppose you find out where that particular electron is. Than you still don't have any clue what it's doing, what it's momentum is.
Suppose you find out what that particular electron is doing, what it's momentum is. Than you still don't have any clue where it is.
This is called the uncertainty principle. You can't know both the location and momentum of an electron. It has been proven that quantum mechanics is indeterministic (of course we still need to question whether the theory is correct, but that's another discussion. Fact is that it's the theory most closely resembling reality).

But are they meaning "indeterministic" in the sense I am?  Sure - we can't know enough about those particles to predict what they will do next.  But what does that imply?  Is it saying that they follow particular rules (and we just don't know what they are), or is it saying that they act in a random manner?

One would assume it is the former, since (when we multiply things up), we "know" that electricity works in a particular way.  It never suddenly doesn't work when most of the electrons go that way instead of this - or does it?

It's random.
The reason why electricity works is because differences in potential are created and therefore moving the probability to find those electrons in a certain direction.

[Anfauglir]

But are they meaning "indeterministic" in the sense I am?  Sure - we can't know enough about those particles to predict what they will do next.  But what does that imply?  Is it saying that they follow particular rules (and we just don't know what they are), or is it saying that they act in a random manner?

One would assume it is the former, since (when we multiply things up), we "know" that electricity works in a particular way.  It never suddenly doesn't work when most of the electrons go that way instead of this - or does it?

It's random.
The reason why electricity works is because differences in potential are created and therefore moving the probability to find those electrons in a certain direction.

Thanks - I think I get it!  So quantum level actions are random, and unpredictable....how does that mesh with operations at "our" level, where things follow particular laws?  How can random happenings at a lower level lead to predictable happenings at the higher level?

[monkeymind]

I don't see how any discussion about determinism (on this forum, especially) can avoid talking about free will.

Well, a good gambit toward steering the conversation away from anthropocentric psychologizing and into purely physical causal determinism might be to toss into the OP some kind of exclusionary codicil.  Say, oh, something like:  

...Now, there are two types of predetermination that we could talk about.  One of them is philosophical predetermination.  This one is the one taken up in religious debates:  Are our actions guided by something?  Basically, it's almost always leads into the 'free will' debate.  But we already have a topic on that one that's doing quite well, actually.

I'm much more interested in scientific predetermination...

APOLOGY: I am in the "Who took a bite out of the moon" stage of my inquiry. Perhaps, it is not appropriate for me to join in on this thread since I am not up to speed.
PROMISE: I won't bring free will up again (even if others do).

From Wikipedia:
http://en.wikipedia.org/wiki/Determinism
Simon-Pierre Laplace's theory is generally referred to as "scientific determinism" and predicated on the supposition that all events have a cause and effect and the precise combination of events at a particular time engender a particular outcome.[8] (my bold)

And if he couldn't avoid the free will issue (or first cause issue), I don't know how we can. Quantum mechanics or not. Persons may use quantum mechanics in an attempt to prove God or spirit, or free will. Trouble is, few people understand the principles. Someone uninformed (like myself) may say, that person really understands quantum mechanics so they may be right.

EDIT: Added...By-the-way everything that I "know" about LaPlace or determinism is what I recall from a 1978 Scientific American article..
I hope you will also cover first cause.

[Max Kodan]

What is all this talk about Electrons?  Why are we still talking about them?  A rock in the air?  What the hell?

Do I need to say this more slowly?  I'm not talking about electrons, I might not even be talking about the way the universe is.

Ok, you know what?  Lemme try something else...I'll be more specific.  Let's assume for a second that string theory is correct, and everything (energy, gravity, matter, and everything in between) is made out of these strings.  I KNOW that there's no reason to believe this is true, but the entire thread has been hypothetical anyway, though most of you seem to have missed that point despite the multiple times I mentioned it.  Now, if everything is made out of Strings, is there a law by which these strings interact?  If there is a law or set of laws that the Strings must follow?  If there is, and there is nothing 'random' about it, then the movements that they would make would be DETERMINED by the LAW.  Again, HYPOTHETICAL.

You can say all you want that electrons are randomly placed just because we can't detect their exact positions.  However, I'm looking beyond what we think we know now.  Perhaps they're not randomly placed, but are guided by a set of laws we simply don't understand yet. 


And this has just been bugging me, your rock analogy. 

First of all the statement is incorrect. If you pause the universe for a moment and you might see a stone in the air, you can't know whether it's just thrown up or already falling down. You also need to know it's speed.
You also need to know all derivatives (which is impossible), but let's suppose you even know that. It still isn't true.

First off, you need to know its momentum, not its speed.  Secondly, if there's air then you can also measure the air currents around the stone.  Thirdly, and this highlights the problem I've had a bunch of times with people in this thread, you're talking about a rock, and I'm talking about the particles that make up the very fabric of the universe.  I think we're on completely different levels of discussion here.

[GetMeThere]

Max,

If you want to talk about how the universe works you can't just IGNORE quantum theory. Many physicists will insist that quantum theory is the very BEST SUPPORTED theory in all of science.

With the inclusion of quantum effects we see that the fabric of the universe is fundamentally UNPREDICTABLE in principle (not just in practice), and is not deterministic.

To address your explicit description: quantum level particles have rules about what they do, but the rules are PROBABALISTIC, not deterministic. It is (again, in principle, not merely in practice) IMPOSSIBLE to know what a single particle will ACTUALLY do, but only the range of probabilities of what it might do. That makes material non-deterministic.

I think you need to do more reading on quantum theory (if I may say so).

[Anfauglir]

To address your explicit description: quantum level particles have rules about what they do, but the rules are PROBABALISTIC, not deterministic. It is (again, in principle, not merely in practice) IMPOSSIBLE to know what a single particle will ACTUALLY do, but only the range of probabilities of what it might do. That makes material non-deterministic.

I think you need to do more reading on quantum theory (if I may say so).

That's the bit I don't get - that particles at the bottom level act in a probablistic manner (that they will probably do this, but may do that), but that this does not translate up to the higher levels - we never suggest that matter will probably fall at a certain rate, for example.

[Str82Hell]

If you consider speed to be a 3D vector it doesn't really matter whether you call it momentum or speed.

[Count Iblis]

If you consider speed to be a 3D vector it doesn't really matter whether you call it momentum or speed.

I hope no one considers speed to be a 3D vector (or any kind of vector at all). Speed is a scalar, velocity is a vector. Speed is the magnitude of the velocity vector.

[/pedantry]

[Count Iblis]

Ok, you know what?  Lemme try something else...I'll be more specific.  Let's assume for a second that string theory is correct, and everything (energy, gravity, matter, and everything in between) is made out of these strings.  I KNOW that there's no reason to believe this is true, but the entire thread has been hypothetical anyway, though most of you seem to have missed that point despite the multiple times I mentioned it.  Now, if everything is made out of Strings, is there a law by which these strings interact?  If there is a law or set of laws that the Strings must follow?  If there is, and there is nothing 'random' about it, then the movements that they would make would be DETERMINED by the LAW.  Again, HYPOTHETICAL.

It is determined by a law, but it's a probabalistic law. Consider a coin toss. It's got a 50-50 chance of being heads or tails. The outcome is random. But I see your objection. If one knew the exact force exerted by the thumb on the coin, the exact angular momentum imparted to it, the exact distribution of mass in the coin, the exact air density, the exact air currents, the exact coefficient of kinetic friction between the air and the coin, the exact coefficient of kinetic friction between the coin and the skin, the exact initial position of the coin, the exact, initial velocity of the coin, etc. and had a computer with infinite precision, etc. then we could predict how the coin would land. These are collectively known as hidden variables. We don't know the values of the hidden variables so we can only treat the system probabilistically.

Quantum mechanically the situation is quite different. An electron is measured to be either spin up or spin down (50-50 chance), for example. Quantum mechanics allows us to calculate this probability. But unlike the coin, there are no hidden variables. They simply don't exist. The buck stops at Schroedinger's equation, so to speak.


Caveat: Dr. David Bohm (of the Aharonov-Bohm Effect fame) did develop a version of Quantum Mechanics with hidden variables. To the best of my knowledge it has never been shown to be false. However, in order to get his theory to work (i.e. be consistent with standard QM) he had to abandon the notion of locality in physics. Physicists generally frown upon such a thing so Bohm's theory never really caught on.

[Max Kodan]

To address your explicit description: quantum level particles have rules about what they do, but the rules are PROBABALISTIC, not deterministic. It is (again, in principle, not merely in practice) IMPOSSIBLE to know what a single particle will ACTUALLY do, but only the range of probabilities of what it might do. That makes material non-deterministic.

I think you need to do more reading on quantum theory (if I may say so).

That's the bit I don't get - that particles at the bottom level act in a probablistic manner (that they will probably do this, but may do that), but that this does not translate up to the higher levels - we never suggest that matter will probably fall at a certain rate, for example.

I have to agree with Anfauglir, to a fairly good extent.  I think there's something more than we're seeing right now.  Obviously I have no proof, nor do I have the means to investigate, but I can't simply accept something like "The universe is purely probablistic" at face value.

However, obviously you've completely missed the point of what I was saying.  This is H-Y-P-O-T-H-E-T-I-C-A-L.  I'm saying that we don't know how the levels of particles will act as they get smaller and smaller.  We used to think that atoms were the be all end all.  Then protons and electrons and neutrons.  We USED to think that everything in the universe followed set rules.  Then all of a sudden Quantum Theory came up, and we found that electrons are probabilistic.  Why can't you accept the fact that maybe...just MAYBE in the future mankind MIGHT discover something that WE DON'T KNOW ABOUT YET that would clear it up, and instead of having a 'probability' we'd have a reason behind the madness.

Now, maybe you should go back and read my posts and realize that I'm not saying that this does definitely coincide with our universe.  Maybe you'll pick up on the 3 or 4 or 5 times I say "In a universe in which there is a law that governs all things at such a certain level..."  So I'm not ignoring your damn theory, I'm going beyond it and quite possibly (Or probably, even) dealing with a different universe entirely.  So if you'd like to do something besides arguing against points that no one's making, please do so now.

Now to prove that you actually read posts rather than just skim them and then repeat what you've already said, here's a question.  Assume this question refers to another universe besides our own.  If there is a set of laws at a certain level of particle, for example the String I talked about in my last post, which all particles at that level must follow; would determinism be a logical conclusion FOR THAT PARTICULAR UNIVERSE?

Also:

If you consider speed to be a 3D vector it doesn't really matter whether you call it momentum or speed.

Totally going in my signature.  Though I will call a partial mistake.  I did mean velocity, not momentum.  However, it still holds:  Momentum just throws mass into the equation.  I guess I was being overly thorough or something...or it was that conversation on another website ~.~...

[GetMeThere]

I can't really continue this argument anymore, because: 1) I don't know enough about quantum mechanics to really say all that's needed, with the precision necessary, and 2) Apparently others are not understanding QM at even a popular level--QM theory is NOT "hypothetical."

And, in fact (as I understand it), gross objects ACT AS ELEMENTARY PARTICLES, in the sense that their exact position and momentum are functions of PROBABILITY, but on a gross level, the probability functions match the deterministic functions so closely that the difference is not seen (as the similar comparisons between relativistic motion vs Newtonian motion).

Honestly, you fellows sound a bit like christians talking about evolution. The basic QM ideas are not out of reach of general readers. Wikipedia has quite a few articles.

My original points, however, relied upon some obvious ways that quantum events can "filter up" into gross action. I gave the examples of the outcome of a long series of collisions being so sensitive that quantum level events affect the final outcome; and I gave the example that quantum level events would affect Brownian motion to the extent that a neuron might fire or not depending on the quantum state of a single elementary particle at a single time.

[Max Kodan]

Huh?  Oh, no no no....I'm sorry, I've been portraying this in the wrong way.  I didn't mean I thought that quantum mechanics are hypothetical, I meant the example I was giving was hypothetical.  I'm terribly sorry, I didn't meant to insinuate that quantum mechanics wasn't backed up by evidence at all, just that I don't think we're getting the whole picture behind it and to assume that we are is just going a little too far.

Though I still notice that you didn't answer the question I posed.

[dloubet]

Your question doesn't work because string theory tries to account for the same evidence that quantum theory does. This means both are accounting for random events.

You'll have to use a universe that doesn't have to account for random events, like the Newtonian universe. That's the classic deterministic universe, and of course, everything in it would be completely deterministic. But that's hardly surprising. 

I know that Einstein didn't like nature throwing dice, so perhaps the Universe of General Relativity would fit the bill? Or do I have that wrong?