A technical question about free will

[jogger08152]

Physicists:

Does quantum physics support, contradict, or not speak to the the idea that humans have free will?

Specifically, how does quantum indeterminacy affect the question of human free will? It seems to me that it ought to increase the likelihood quite a bit, relative to the classical idea of a universe in which, if the state of all things were known absolutely at any given point in time, the outcomes of all interactions could be calculated precisely, given enough computing power.

Thanks,
Jogger

[Skidoo]

If I understand you right, please explain how indeterminacy (of any sort) could cause or otherwise improve self-determinacy.

You volunteered this opinion, so I'm curious how you got there.

[jogger08152]

In classical physics, the supposition existed that if you could know everything about the universe at a given time (the "state" of the universe), you could use that knowledge (given vast, Godlike computing power), to precisely predict all future states of the universe (and could, I think, extrapolate backwards to predict all past states as well).

This idea, which I understand quantum physics to contradict, seems to me to be incompatible with free will: while I might believe, for instance, that I can either turn right at the next stop sign I encounter or instead proceed through the intersection, in fact, a precise prediction could have been made (theoretically) as to which direction I would "choose" 20 million years before my birth, or indeed, .0000001 seconds after the Big Bang. In other words, in classical physics, my "choice" would be predetermined, and therefore (at least it seems to me), not really a choice at all. The laws of physics and the "motion" of the universe would have determined (pre-determined, in fact, as in predetermined causally) my actions. This in turn would seem to proscribe the possibility of my having free will.

In quantum physics, as I understand it, the universe doesn't work deterministically, but instead is governed by probability. Simply, if you could know the state of the universe at any given time - but quantum physics applied - you could not use the knowledge to predict the future state of the universe. (Actually, I believe I may be expressing this incorrectly: quantum physics may deny the possibility of knowing the state of the universe in the first place.)

Again, disregard the difficulties of obtaining the knowledge and of making perfect predictions based upon it. The point is, in classical physics, with perfect observation and a powerful enough computer, you could do it. In quantum phsyics, you can't - I think. But I'm not sure. My understanding of all of this is limited - hence my request for clarification.

-J

[ChrisV]

Quantum physics implies some kind of hole in determinacy, but it depends on what interpretation you apply. In the Copenhagen Interpretation, the future is not predetermined, which is good news for free will. In other interpretations, such as the Transactional Interpretation, the future has in some sense already happened, as there are backwards in time signals in this interpretation. However it is still not possible to determine the future from the universe's present state.

[Nielsio]

[ QUOTE ]
In other words, in classical physics, my "choice" would be predetermined, and therefore (at least it seems to me), not really a choice at all.

[/ QUOTE ]


Choice is a causal mechanism.

[DrunkHamster]

I just finished writing a philosophy essay on this topic - I don't know that much about the physics, but philosophically it is very interesting:

You are really asking 2 questions: does physics support determinism (i.e. the thesis that a proposition A detailing the state of the universe at time t, and L the laws of physics together entail B, the state of the universe at some time after t.) This is not known conclusively - look here (http://www.ucl.ac.uk/~uctytho/Determinism.pdf) for an article on why.

The other question, which occupies philosophers much more, is whether or not if determinism were true free will would exist. The best people to read on this subject are Van Inwagen, Ayer, and probably Strawson. A nice web page by Honderich (who is closely involved in the argument) is here (http://www.ucl.ac.uk/~uctytho/dfwIntroIndex.htm)

[Skidoo]

[ QUOTE ]
Choice is a causal mechanism.

[/ QUOTE ]

Proof?

[jogger08152]

I can't follow the math in the first article; can you explain why we don't know whether physics supports determinism (or do you have a link to an explanation of this) in lay terms?

The second link looks promising; I just finished Determinism's Consequences -- The Mistakes of Compatibilism and Incompatibilism, and What Is To Be Done Now, and it seems most people take the existence of free will to be the axiomatic starting point (I haven't read any of the sublinks in part 8 yet though) and concentrate mainly on explaining its nature. Is this correct? In other words, it seems people are mainly interested in finding a way to allow determinism and free will to coexist because they believe they experience free will, and they think there is a good chance the universe is deterministic. This strikes me as kind of a weird approach: because the experience of free will is more compelling (to me) than the belief in a deterministic universe, I find myself thinking there must be something wrong with determinism. But then I don't see any need to rationalize the two, since if the universe is deterministic, there's no reason I can think of why it couldn't exist in such a way as to fool me into thinking I have free will even though I don't actually have it. (I don't think this is the case, mainly because of Occam's razor: most likely the universe simply isn't deterministic, which seems to gibe with quantum physics. Hence my original question.)

Anyway, thanks very much for your reply!

Best regards,
Jogger

PS - you mentioned writing an essay on this topic recently; would you mind sharing what you discussed? (You're welcome to PM me if you'd like.)

[Skidoo]

[ QUOTE ]
But then I don't see any need to rationalize the two, since if the universe is deterministic, there's no reason I can think of why it couldn't exist in such a way as to fool me into thinking I have free will even though I don't actually have it.

[/ QUOTE ]

Not that either of us is right or wrong here, but this is the second seemingly incomprehensible concept you've introduced in this thread (in fact, it's probably a good thing).

First was your suggestion that non-determinacy is an improvement over pre-determinacy as a basis for self-determinacy. This was more of a question by you than an assertion, so I'm not calling on you to prove it or anything.

Now it's this notion of the illusion of free will. How is this even possible, in your opinion? If you attempt to exercise what you think is free will and then you exercise it, it's free will. In other words, how can unfree will exist?

[arahant]

Free will is definitely not taken as a given by most modern, intelligent people. The compatiblists are just kind of reaching...

In response to your original question:
Does it actually matter whether the universe is deterministic or not? If you have some kind of quantum switch in your head that results in your decisions being 'truly' random, does this constitute free will? It's important to note that the indeterminacy of quantum physics (in interpretations that posit indeterminism) is not a question of ignorance, but of genuine randomness. There is no underlying mechanism that WE can't predict, the mechanism is simply unpredictable by nature.

Further, quantum effects aren't really relevant for the human brain. Even assuming that your choices WERE somehow randomized as a result of quantum indeterminacy, your perception of how you arrived at those choices (i.e., your illusion of free will) would be no different than if they were 'deterministic'.

[jogger08152]

[ QUOTE ]
If you attempt to exercise what you think is free will and then you exercise it, it's free will. In other words, how can unfree will exist?

[/ QUOTE ]
If you're asking about the "mechanism" by which this might work, I have no idea. But I can't escape the idea that, if all of my actions could be predicted with absolute certainty before I was born, I cannot have true free will. Having said this, obviously I have the perception that I have free will, in the sense that even though I'm typing this sentence right now, it sure *feels* like I could stop, if I wanted to. However, it seems to me that if the universe is deterministic in a manner that allows my actions to be predicted (with 100% certainty, of course), it must be the case that even though I feel like I have free will, in fact I don't. This, even though the deterministic factor/s that counterfeits my free will while still allowing me to (wrongly) believe I have it, is beyond my comprehension.

The upshot of all this is that it seems to me that the universe probably isn't deterministic, and my understanding of quantum physics (such as it is) also seems to support the notion of a non-deterministic universe. (Which is why I asked my question; basically I want to back-check whether or not Q.P. actually does support a view of the universe as non-deterministic.)

Best regards,
Jogger

[jogger08152]

[ QUOTE ]
In response to your original question:
Does it actually matter whether the universe is deterministic or not?

[/ QUOTE ]
I think it matters a great deal, yes. It seems to me that a universe that is completely deterministic, that is, whose future interactions are all perfectly predictable given some present set of knowledge, would automatically preclude free will, since free will implies the ability to make choices that potentially affect outcomes. (Thus, if the outcome is already known, then my "choices" that lead to it must also be known, and therefore are in some sense, "immutable in advance", and thus aren't really choices at all. Instead they would have to be, in some form, mere consequences of the laws of the universe.)


[ QUOTE ]
If you have some kind of quantum switch in your head that results in your decisions being 'truly' random, does this constitute free will? It's important to note that the indeterminacy of quantum physics (in interpretations that posit indeterminism) is not a question of ignorance, but of genuine randomness. There is no underlying mechanism that WE can't predict, the mechanism is simply unpredictable by nature.

[/ QUOTE ]
To the extent that quantum physics tells us that our universe - and therefore, our choices - are not predictable in this way, it increases the likelihood of free will. It does not necessarily, and need not, constitute it. (Of course, maybe it does something else that I'm not aware of or not thinking of, that would also preclude free will. But absent this, quantum physics as I understand it (note though, that my understanding is second hand, at best that of a decently bright lay person without the scientific skills necessary to verify the explanations/summaries I've run across) does seem consistent with my perception that I have free will.)

Best regards,
Jogger

[Sephus]

[ QUOTE ]
To the extent that quantum physics tells us that our universe - and therefore, our choices - are not predictable in this way, it increases the likelihood of free will.

[/ QUOTE ]

if they're predictable according to probability distributions instead, it doesn't seem to make free will any more likely.

[Brom]

Here's a quote from a Wiki article that pretty much sums up what I thought on the compatability of quantum physics with determinism;

"So quantum mechanics is deterministic, provided that one accepts the wave function itself as reality (rather than as probability of classical coordinates). Since we have no practical way of knowing the exact magnitudes, and especially the phases, in a full quantum mechanical description of the causes of an observable event, this turns out to be philosophically similar to the "hidden variable" doctrine."

Link (http://en.wikipedia.org/wiki/Determinism#Determinism.2C_quantum_mechanics_and_c lassical_physics)

[Metric]

[ QUOTE ]
The upshot of all this is that it seems to me that the universe probably isn't deterministic, and my understanding of quantum physics (such as it is) also seems to support the notion of a non-deterministic universe. (Which is why I asked my question; basically I want to back-check whether or not Q.P. actually does support a view of the universe as non-deterministic.)

[/ QUOTE ]
The way quantum physics balances determinism and probability is extremely subtle. Extremely subtle. Only now is a really good understanding of this emerging, in the context of quantum information theory. One way to describe the situation is this: the full quantum state of the universe evolves in a completely deterministic way -- however, the information obtained by one quantum subsystem (an observer) about another quantum subsystem (say, an atom), is inherently probabilistic. This may seem contradictory on the surface, and indeed the entire 20th century had to pass before people really began to nail this concept down.

[jogger08152]

Metric,

How firm is this idea?

Thanks,
Jogger

[Metric]

It is pretty solid, being a result from within the established quantum information formalism itself, rather than a new postulate looking for someone to adopt. On the other hand, there are only a handful of papers on this particular subject, so by no means are all the implications explored yet.

[Piers]

[ QUOTE ]
Does quantum physics support, contradict, or not speak to the the idea that humans have free will?

[/ QUOTE ]

not speak to.

I think to understand free will it is best to consider the brain as an organic computer. Somewhere between the biochemical level (Hardware) and the discharge of thoughts moving through the brain (software) it should eventually be possible to isolate the patterns that generate the sensation of free will.

Quantum physics is at a completely different level. Might as well use quantum physics to determine how long to microwave a frozen pizza.

[ QUOTE ]
the state of all things were known absolutely at any given point in time, the outcomes of all interactions could be calculated precisely, given enough computing power.

[/ QUOTE ]

This does not necessarily follow. And not only because its neither possible to know the state of all things nor have enough computing power. And it has nothing to do with the sensation of free will, which a consequence of certain biochemical processes in the brain.

[madnak]

Being brief.

[ QUOTE ]
if all of my actions could be predicted with absolute certainty before I was born, I cannot have true free will

[/ QUOTE ]

What is "true free will?"

[ QUOTE ]
obviously I have the perception that I have free will,

[/ QUOTE ]

That's not obvious to me. Can you explain why it should be?

[ QUOTE ]
in the sense that even though I'm typing this sentence right now, it sure *feels* like I could stop, if I wanted to

[/ QUOTE ]

If you wanted to stop, then there would exist a cause for your stopping (the desire to stop typing). The statement "if" here represents a causal contingency - how is this consistent with your presentation of free will (which you have described as being the opposite of causal contingency)?

[ QUOTE ]
I think it matters a great deal, yes. It seems to me that a universe that is completely deterministic, that is, whose future interactions are all perfectly predictable given some present set of knowledge, would automatically preclude free will, since free will implies the ability to make choices that potentially affect outcomes. (Thus, if the outcome is already known, then my "choices" that lead to it must also be known, and therefore are in some sense, "immutable in advance", and thus aren't really choices at all. Instead they would have to be, in some form, mere consequences of the laws of the universe.)

[/ QUOTE ]

This isn't a valid argument, and it doesn't work as an appeal to my intuition (partly because I think the intuition of "free will" is essentially a western cultural construct in the first place, partly because appeals to emotion just aren't valid rationally, and partly because I have no such intuition and so the example fails to resonate and seems like nonsense to me).

The outcome can only be predicted if you can fully identify and calculate the effects of every event preceding it, including your choices. Thus, your statement amounts to "if I know for a fact what I'm going to choose, then I can't choose otherwise." While tautologically true, this statement is completely circular and has no apparent relevance to determinism, free will, or physics.

[Skidoo]

[ QUOTE ]
Might as well use quantum physics to determine how long to microwave a frozen pizza.

[/ QUOTE ]

Quite right. And besides, I would question how this notion of accounting for free will with incompleteness ever got started. A system not having a unique state does not give it the ability to choose its state. That's apples and oranges.

[jogger08152]

[ QUOTE ]
What is "true free will?"

[/ QUOTE ]
The ability to select one of two or more mutually exclusive courses of action, attempt the action, and influence the universe (most likely in a very minor way) thereby, such that if I had chosen to act differently, a different outcome would have resulted. An adequate definition of free will as a doctrine is available on dictionary.com: "-noun, Philosophy. the doctrine that the conduct of human beings expresses personal choice and is not simply determined by physical or divine forces. " [Emphasis mine -Jogger]

[ QUOTE ]
That [my perception of having free will]'s not obvious to me. Can you explain why it should be?

[/ QUOTE ]
I perceive myself to make choices all the time. I assume this perception is common to everyone. However, if you have no sense that you are able to make choices, there's probably nothing for us to discuss in this area.

[ QUOTE ]
If you wanted to stop, then there would exist a cause for your stopping (the desire to stop typing). The statement "if" here represents a causal contingency - how is this consistent with your presentation of free will (which you have described as being the opposite of causal contingency)?

[/ QUOTE ]
Where have I so described it? On the contrary, if free will exists I think it must be causal, in the sense that it (and the actions that flow from it) must exert an influence on "what happens next". Only if it is not able to influence future events - as would seem to be the case if everything is predetermined - would it *not* be causal.

[ QUOTE ]
Thus, your statement amounts to "if I know for a fact what I'm going to choose, then I can't choose otherwise." While tautologically true, this statement is completely circular and has no apparent relevance to determinism, free will, or physics.

[/ QUOTE ]
It isn't relevant whether or not I know what "choices" I will make. What would be relevant would be if someone (with vast knowledge and computational ability, of course) could predict them unfailingly before I was born.

[ QUOTE ]
[ QUOTE ]
I think it matters a great deal, yes. It seems to me that a universe that is completely deterministic, that is, whose future interactions are all perfectly predictable given some present set of knowledge, would automatically preclude free will, since free will implies the ability to make choices that potentially affect outcomes. (Thus, if the outcome is already known, then my "choices" that lead to it must also be known, and therefore are in some sense, "immutable in advance", and thus aren't really choices at all. Instead they would have to be, in some form, mere consequences of the laws of the universe.)

[/ QUOTE ]

This isn't a valid argument, and it doesn't work as an appeal to my intuition (partly because I think the intuition of "free will" is essentially a western cultural construct in the first place, partly because appeals to emotion just aren't valid rationally, and partly because I have no such intuition and so the example fails to resonate and seems like nonsense to me).

[/ QUOTE ]

In what way is this argument invalid? Do you see a way in which determinism and free will might not be mutually exclusive? Maybe you define free will differently than I do; as I think about it this seems likely from your first question (and your assertion that you don't seem to experience it).

Best regards,
Jogger

[arahant]

FWIW, I approach this problem from a different direction.

There is really no reason to believe in 'free will' beyond some people's subjective experience. I, too, don't really have a sense of 'free will'...rather, I can feel, and gain some insight into, the way I (my brain) makes decisions.
A number of experiments have been done which indicate that people have a sense of 'free will' even when their actions are not voluntary, so the subjective sensation of itself provides no evidence for the existence.

We have yet to identify any possible mechanism that could account for the interaction of some mystical 'free will' and regular matter (a requirement, obviously). I won't argue about whether QM ALLOWS for 'free will' (I don't think it does...), but it certainly provides no MECHANISM.

It doesn't seem to me to be possible to ever reach a level of knowledge that would exclude free will....just like God, we can always just change the definition to fit every new understanding of the universe. Even within classical mechanics, one can always claim that there are minute and immeasurable 'free will effects' in the brain.

So to me, the more important question is, 'why would you think free will existed?'.

[madnak]

[ QUOTE ]
The ability to select one of two or more mutually exclusive courses of action, attempt the action, and influence the universe (most likely in a very minor way) thereby, such that if I had chosen to act differently, a different outcome would have resulted. An adequate definition of free will as a doctrine is available on dictionary.com: "-noun, Philosophy. the doctrine that the conduct of human beings expresses personal choice and is not simply determined by physical or divine forces. " [Emphasis mine -Jogger]

[/ QUOTE ]

The second definition doesn't follow from the first. Nothing in your first definition implies that a choice is not itself a physical or divine event.

[ QUOTE ]
I perceive myself to make choices all the time. I assume this perception is common to everyone. However, if you have no sense that you are able to make choices, there's probably nothing for us to discuss in this area.

[/ QUOTE ]

Nobody is arguing that we don't make choices, or that they don't affect outcomes. This is especially true depending on your definition of "choice" - if a choice is simply a selection of one options from a group of options, then choices are clearly deterministic - a supercomputer chess program can defeat you, but if it chose to make different moves then it wouldn't. You've failed to explain why a human making moves in a chess game is different from a computer making moves in a chess game - both consider the possible (legal) moves, evaluate the outcomes, and form a decision based on criteria such as effectiveness (likelihood that the move will result in a positive outcome). You've presented no reason to believe that the fact human beings experience their choices subjectively (while computers, presumably, don't) somehow means that the decisions people make aren't based on concrete standards and criteria. Even if you were to establish this, the leap to some supernatural or nondeterministic mechanism would still be wholly unjustified.

[ QUOTE ]
Where have I so described it? On the contrary, if free will exists I think it must be causal, in the sense that it (and the actions that flow from it) must exert an influence on "what happens next". Only if it is not able to influence future events - as would seem to be the case if everything is predetermined - would it *not* be causal.

[/ QUOTE ]

First, "predetermination" isn't analagous to determinism. It's largely a straw man. A full determinist does believe that there is only one course the future will take - that doesn't meaningfully imply that such a future is "predetermined," only that its events are causally dependent upon preceding events (and such events can very well include choices).

[ QUOTE ]
In what way is this argument invalid? Do you see a way in which determinism and free will might not be mutually exclusive?

[/ QUOTE ]

Gotta go, I'll cover the rest later. But in answer to this, I think Hume covered it nicely (http://en.wikipedia.org/wiki/Compatibilism).

[Skidoo]

[ QUOTE ]
You've failed to explain why a human making moves in a chess game is different from a computer making moves in a chess game

[/ QUOTE ]

No one has proven anything either way. On the other hand, why assume an essentially equivalence when their effects are so profoundly different?

[ QUOTE ]
First, "predetermination" isn't analagous to determinism.

[/ QUOTE ]

Either the course of events is uniquely determined by preceding conditions or it isn't.

[Bill Haywood]

I can show you how quantum mechanics creates the ILLUSION of free will.

Our perception of free will depends on the belief that the universe is not predetermined -- we can make choices.

A Newtonian universe of only clacking pool balls really would be fixed. But there is one thing out there that is not predetermined. According to my crude understanding of quantum physics, one implication is that the precise moment when a radioactive particle decays cannot be predicted. Radioactive breakdown introduces heat, therefore it impacts events. And since a butterfly in Brazil creates tornadoes in Kansas, the indeterminacy of radiation has endless effects.

It is because the universe has genuine randomness that we can preserve a sense of free will.

Our future is not fixed by fate, but unfortunately, we can't fix it either. But it's pleasant feeling like we can.

[jogger08152]

Madnak,

The link is fantastic, thanks very much!

As far as your other comments, this one is the most important from my perspective:

[ QUOTE ]
Nobody is arguing that we don't make choices, or that they don't affect outcomes.

[/ QUOTE ]
Actually I'm making that argument, but I'm making it conditionally. It seems to me that if the universe is wholly deterministic, then we don't make choices (even though we feel like we do). If we do make choices, then the universe is not wholly deterministic.

The wiki link you provided contrasts the positions of hard determinists with those of (free will, not political) libertarians, indicating that the former believe the universe is deterministic and that therefore there is no free will, whereas the latter believe that there is free will and that therefore the universe cannot be deterministic.

Absent any physical knowledge, as MJC says, "all bets are even money" - there's no reason to prefer one viewpoint over the other. Except: I do perceive myself to be exercising free will. This, for me at least, lends credence to the libertarian conclusion. The problem is, in Newtonian physics, the position of the hard determinists seems to come off much better than that of the libertarians, which throws the issue back into question. My question simply had to do with whether quantum physics offsets or supercedes the Newtonian problem, and the author of the article notes that this possibility is "out there", advocated by Roger Penrose among others. That's more or less what I wanted to know: it sounds like at least some quantum physicists do believe QP throws favorable light on the possibility of free will.

So, thank you for your help. This covered exactly the material I was interested in.

Best regards,
Jogger

[Metric]

Just FYI, although Roger Penrose is a brilliant guy and truly a deep thinker of physics, a large majority of quantum physicists (including myself) think he's "just plain wrong" on a couple of speculative issues that he likes to talk about, including in particular 1)the "quantum consciousness stuff" and 2) his gravitationally induced "objective reduction" stuff, though the latter appears to be experimentally testable, and so retains some status as a respectable idea.