I think that QM does not favor free will, any more than Classical Mechanics does, and here is my reasoning:

  1. QM predicts odds, but that doesn't mean we are free, right? To be free, we will have to change the odds in our favor, so to speak. Maybe I don't understand probability well, but it seems to me that fixed odds still mean no free will.

  2. The laws of QM have been shown (somewhat) to give the same results as Classical Mechanics at macroscopic scales. So all the previous arguments about whether there is free will or not can continue to be valid (I suppose).

So, what is wrong with this reasoning?

  • Well, at least we know quantum systems can't be simulated in real-time on deterministic machines. This means determinism is too weak. But are quantum effects noticeable in our behaviour? This is the question?
    – rus9384
    Commented Apr 5, 2018 at 16:05
  • Just pointing out in case it's unknown to anyone: even as a determinist you can think that free will exists. This is called compabilitism. The SEP has a quite detailed article which goes into multiple objections. plato.stanford.edu/entries/compatibilism
    – Marc H.
    Commented Apr 5, 2018 at 21:35
  • It is called quantum theory because the causes and effects occur at a quantum level - not at a gross level. Does your thinking occur in a Brownian motion manner? If it did there would be complete chaos at the gross level - which there is not. Commented Apr 6, 2018 at 4:49

4 Answers 4


First, the problem of free will might be the most difficult problem in philosophy. Mixing it with quantum mechanics hardly helps. Second, I think the simple answer is that quantum mechanics does not imply free will. The word 'imply' is probably too strong here. What quantum mechanics does do for the cause to imply that determinism is false.

A couple points:

  1. It's probable that no scientific theory will ever imply free will. This is because our concept of free will appears to be impossible to articulate. And the simple lack of determinism does not satisfy our intuitive sense of free will. Take for example completely non-deterministic random behavior: suppose my arm started behaving randomly, swinging this way and that with no dependency on any antecedent cause (and uncaused by me). I would hardly want to call that free will--especially since I have no control over it! So it seems that free will is something else, or at least something in addition to a lack of determinism.

Here is a quote I really like by Thomas Nagel in his book 'The View from Nowhere:'

I change my mind about the problem of free will every time I think about it, and therefore cannot offer any view with even moderate confidence; but my present opinion is that nothing that might be a solution has yet been described. This is not a case where there are several possible candidate solutions and we don't know which is correct. It is a case where nothing believable has (to my knowledge) been proposed by anyone in the extensive public discussion of the subject.

The difficulty, as I shall try to explain, is that while we can easily evoke disturbing effects by taking up an external view of our own actions and the actions of others, it is impossible to give a coherent account of the internal view of action which is under threat. When we try to explain what we believe which seems to be undermined by a conception of actions as events in the world — determined or not — we end up with something that is either incomprehensible or clearly inadequate.

  • 1
    So, before arguing whether there is free will or not: maybe we wouldn't even be able to reliably recognize free will if we observed it. (sometimes a concept is hard to define, but easy to recognize - maybe free will is either not easy to recognize [experimentally] or even fundamentally not observable by experiments) Commented Apr 6, 2018 at 20:48
  • 1
    @cbeleites Interesting comment. Like consciousness, I recognize my free will—I would even say that I observe it in myself. However, in others, like consciousness, I can only assume they possess it. A key problem with consciousness is that it doesn't appear to be something we can observe in others—only ourselves. Therefore, a scientific description seems unlikely. Free will might also be like this—something we experience internally, but can't observe in others.
    – njs
    Commented Apr 6, 2018 at 21:26
  • Yes, I was talking about observing it in others - as that is required for tackling the issue experimentally. I very much like your link with consciousness. (Also, because in the descussion of free will sometimes a lot of emphasis is put on being conscious of excercising the free will - with which I do not wholly agree from a macroscopic practical point of view: we spend much effort on our perceived free will to automate decisions and actions so we do not need to spend consciousness on them.) Commented Apr 7, 2018 at 14:40

I'm pleased by your point 1), because changing the odds in our favor draws attention to the will in free will, whereas people are constantly focusing on the free.

Yes, I think you have a point: the behavior of quantum things is free, but there is absolutely no indication that these things have a will, as with human decisions.

  • 1
    +1 However, I think BlowMaMind wants to know whether we have free will, not the quantum system. You bring up a good point about the need for defining what "free will" is. Commented Apr 5, 2018 at 16:43
  • If I understand the OP, materialism is taken as the hypothesis, and "free will is evidence against" is point A, while "but QM things are unpredictable, too" is supposedly a defeater to point A. The OP wants to show that there isn't a good enough analogy between "QM things are unpredictable" with "people are unpredictable" to defeat point A. Thus, in the OP's opinion, very likely the hypothesis is invalid. Commented Apr 5, 2018 at 16:53
  • 1
    The claim of Conway and Kochen was that if human have free will, the same kind of free will is observable in quantum particles.The wikipedia entry en.wikipedia.org/wiki/Free_will_theorem provides links. All of this and more of the same has been already discussed around here.
    – sand1
    Commented Apr 5, 2018 at 21:17
  • 1
    A quick read by me does not reveal any aspect of will ascribed to particles. Commented Apr 5, 2018 at 21:22
  • @elliotsvensson There isn't "will" as we are used to seeing it requiring a brain to rationally come to a decision in the Conway and Kochen free will theorem. We would need to redefine free will or expand what it means. I like your answer because it starts to pick apart "free will". Commented Apr 5, 2018 at 21:49

Even in a deterministic universe, free will could be experienced subjectively. Identity, and attributing motivations to it, would only have to be more computationally manageable and provide better predictions, to demand the benefit of Occam's razor heuristically. Further, as David Deutsch pointed out in his The Fabric Of Reality, emergent complexity requires more than one explanatory layer, irreducible to each other.

So, free will is a subjective experience, even in a quantum world. It is convincingly derivable from emergent dynamics. These do not intrinsically rely on a quantum mechanical explanatory layer in the same way a computer program doesn't rely on a computers specifics. Although the complete refutation even in principle of explanation by reference to a lowest reductionist explanatory layer helps dismiss any doubts about that.

Edited to add: To be clear emergent here relates to it's use in systems dynamics https://en.m.wikipedia.org/wiki/Emergence

  • The Stanford Encyclopedia of Philosophy's entry on Emergent Properties is not kind to the notion that a substance, such as free will, is attributable to emergence. plato.stanford.edu/entries/properties-emergent Commented Apr 5, 2018 at 21:47
  • @elliot svensson: You have the wrong context of emergence.
    – CriglCragl
    Commented Apr 5, 2018 at 22:00
  • Pretty sure that Wong and O'Connor '15 is related to the entire notion in philosophy. They begin with "Emergence is a notorious philosophical term of art. A variety of theorists have appropriated it for their purposes ever since George Henry Lewes..." plato.stanford.edu/entries/properties-emergent Commented Apr 5, 2018 at 22:21

QM being unpredictable is likely due to the limits of human understanding, and so using it as the lynchpin in any philosophical discussion would be the same as using the sun disappearing and reappearing to confirm the existence of a higher power.

The case for free will hinges upon the human mind being able to deviate from the otherwise seemingly deterministic nature of the universe, and quantum mechanics is a nice get out clause for that, however then we have to argue that the human brain can affect quantum mechanics, whilst being driven by something other than quantum mechanics, otherwise it is just QM affecting itself, and leaves us no more free than in a deterministic universe.

  • It would be more like using that one unusually warm day to disprove global warming. See 'No extension of quantum theory can have improved predictive' powerhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3265370/
    – CriglCragl
    Commented Apr 6, 2018 at 0:02
  • Nicolas Gisin has written some notable things on the topic, the latest being from two weeks ago arxiv.org/pdf/1803.06824.pdf
    – sand1
    Commented Apr 6, 2018 at 9:04
  • 1
    How do you arrive at the "likely"? (I'd immediately have agreed with could) Commented Apr 6, 2018 at 20:38
  • 1
    @cbeleites 'Likely' might be too strong a word, but I base it on most assumptions in the past being shown to be due to the limits of human understanding. I agree with 'could', also. Commented Apr 7, 2018 at 10:45
  • Your statement "QM being unpredictable is likely due to the limits of human understanding" is a common belief. Einstein held this belief and thought that QM was incomplete and that hidden variables existed that simply were not yet part of the theory. However, John Bell showed that adding local hidden variables to QM introduced contradictions. The conclusion was that QM is a complete theory--you can either accept it or reject it, but you can't add anything else to it or say it's incomplete. If you do reject it, however, you are rejecting the most successful theory in the history of physics.
    – njs
    Commented Apr 7, 2018 at 22:42

Not the answer you're looking for? Browse other questions tagged .