By understanding the laws of nature, I've come to the conclusion that everything evolves according to the laws of physics, and that includes the formation of conscious and unconscious thoughts in the brain. If we consider the brain to be a system of particles, then that system evolves with a given set of laws: and though the final state of the system might be unpredictable (due to quantum mechanics), we can say that the thoughts are determined, by the universe - whatever that means.

This would imply that a computer simulating the number of particles in a brain will also claim that it is conscious; yet since a computer evolves in a predictable deterministic fashion, a computer simulating the brain and the brain itself will branch out given some time, due to the microscopic changes that occur in the latter by virtue of unpredictable quantum mechanical events.

So given this, how are proponents of free will defending their case? To me it seems that anything that is free to make a decision should therefore be beyond the physical plane; i.e., in a universe that doesn't have the same familiar laws as ours. Our universe provides a natural way for consciousness to come into being and any invocation of external agency seems very unrealistic to me.

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    There are lots of defences that could be given. Please review the other questions tagged free-will, we already have a lot. Aug 28, 2019 at 13:18
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    So our behaviour is determined by the brain, the brain by the chemistry of our body, chemistry by quantum laws, quantum laws by Big Bang. In the end the Big Bang is the only "entity" responsible for John killing is friend Jack... Aug 28, 2019 at 13:23
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    But we cannot put in jail the Big Bang: thus, we decide to put John is jail. In the end, he is at least accomplice with the Big Bang. Aug 28, 2019 at 13:25
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    Thus, apes have free will. Aug 28, 2019 at 13:39
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    Any complex of particles that has truly non-deterministic behavior, which is every complex of particles, is making decisions. Unless you believe in the magic of human agency as an input to physics via the observer effect as part of your determinism, which seems quite disparate, the questionable part of free will is the will part, not the free part. Quantum uncertainty gets grounded as larger and larger contingents of particles join the consensus of 'wave collapse', but it is genuinely not deterministic.
    – user9166
    Aug 28, 2019 at 15:13

4 Answers 4


I see two main avenues. Compatibilism, and pantheism.

Compatibilism typically says free-will is a profoundly useful heuristic, and it plays a role in one of the explanatory layers that make predictions tractable, and exist above quantum field theory but reducible to it in principle. Specifically, in the layer about predicting oneself and others in social space, and allocating moral sentiments. Take a thought experiment: Given a sufficiently complex mind (humans already have more neurons than stars in the Milky Way), with interconnections rising way faster than volume, it may become impossible even in principle to predict what it will do using matter-energy & time available in the universe, except by being the mind (initial conditions problem). And if the closest predictions are based on heuristics, those become part of the best physics model. The will of a god, so to speak.

Pantheism is more respectable than you may realise. People outside of physics often don't realise our theories are currently property dualist, with the substances being energy and information. Information was thought to be an accidental property of mass and energy, but information effects like entropy and the speed of light turn out to be as deep as conservation of energy. In fact conservation of information is a posited but not proven concept, used to solve the blackhole information paradox. Wheeler, my favourite physicist, proposed the 'It From Bit' doctrine, the idea information is the fundamental layer, not mass-energy. Specifically he framed it as everything at it's core coming down to a series of yes and no answers.

An information-fundamental universe is a type of pantheism. Minds in it don't create but only concentrate what is fundamental to the universe. OrchOR is a model of consciousness along these lines.

Quick precis anyway. Do the leg work and ask less general questions.


Determinism is an illusion due to quantum physics.

"This would imply that a computer simulating the number of particles in a brain will also claim that it is conscious yet since a computer evolves in a predictable deterministic fashion."

If you make a computer that simulates particles, it will be deterministic since the macroscopic world follows rules that on average appear to be deterministic. But our universe is not made of particles. If your computer would really simulate the behavior of the quantum realm, it cannot be deterministic. Take your conclusions regarding free will and the meaning of it.

See my answer here to an ideal of determinism: https://physics.stackexchange.com/questions/437495/can-any-body-be-uniform-in-the-universe/437516#437516


As some of your commentators have pointed out, neither the problem nor responses to the problem are obscure. This is a central question in philosophy. See both posts with the free-will tag or the WP article free will to start you on a path to an answer.

However, that being said, let's throw out a teaser.

You claim that the laws of physics supervene on higher domains of truths, such as chemistry or anatomy and physiology of the brain, and presume that the laws of physics are deterministic, but are they? Causality is largely taken to be an abstraction of the mind, and fails in some ways in regards to being a metaphysical foundation. For instance, if nothing in the universe can travel faster than the speed of light, how does one explain quantum entanglement? And how do you deal with an argument that argues that free will is byproduct of emergence? In fact, quantum physics is largely viewed as having killed the deterministic Newtonian universe. Anyway, as a student of computers, I can tell you the same thing that Arno Pensias arrived at in his book Ideas and Information. Computers and human minds are not similar in regards to their creation and use of semantic content. Computers don't really have any. Is that because the von Neumann architecture is wholly deterministic and the human brain is not? (Human thought certainly has non-deterministic behavior in the same way electrons also are probablistic.)

Your certainty is laudable, but considering that the problem is an ongoing philosophical conversation, your self-confidence might be a bit misplaced.

  • How can you assert that if a computer doesn't have "semantic" understanding, that a human being is any different? Why do we claim we understand anything for that matter, if knowledge is representable as a state of the body at any given time. But then you must define exactly what you mean by time because according to the best evidence available today, time seems to be quantized just like energy. So there is no exact moment in time, where we can point out and say a human understands. The other argument is that humans are physical systems just like machines. Hence it inherits machine properties.
    – Weezy
    Mar 16, 2020 at 6:51
  • What I'm saying is, on surface levels, if one chooses to ignore quantum indeterminacy and its possible link with human consciousness or any other being's consciousness, observing the human being in question, then to the observer, this human appears fairly deterministic and hence you have a field of psychology where behaviourism is practiced to sufficiently predict exactly that. To a behaviourist, understanding means nothing, but certainly doesn't feel like that to the conscious agent in question. I want to point out the extra non-computable factor that differentiates the human from the machine
    – Weezy
    Mar 16, 2020 at 6:54
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    @Weezy Because I'm finishing up my MS in CS and I understand how computers work almost down to the transistor. I'm not saying it's not possible. Indeed, I believe it is almost assured they will someday. See my post on epistemology and computers.
    – J D
    Mar 16, 2020 at 13:14
  • @weezy I'm aware of no legitimate scientific research that purports to show a link between consciousness and quantum principles other than perhaps Penrose's work on the subject which seems to be metaphysical speculation rather than quality proof.
    – J D
    Mar 16, 2020 at 13:17
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    @CriglCragl So noted. I'll give it a good gander.
    – J D
    Mar 17, 2020 at 16:15

By understanding the laws of nature, I've come to the conclusion that everything evolves according to the laws of physics, and that includes the formation of conscious and unconscious thoughts in the brain.

A side-point, first... Even if I grant the conclusion (which seems reasonable in a tautological sort of way), I have to point out that there is a conceptual chasm between 'the laws of physics' and 'our understanding of the laws of physics.' Physics is a set of models about how the world works, and as accurate as those models may be, a model is never more than a loose description of those aspects of reality that happen to catch our attention. We don't 'know' that the laws of physics are deterministic: the 'Clockwork Universe' is a holdover from 18th century philosophy that is gradually eroding under modern research.

But putting that aside, this is the kind of philosophical question that the later Wittgenstein thought needed therapy rather than an answer. What use does this question have? We have the subjective experience of free will — we perceive ourselves as having the power to make free choices and decisions, perhaps within certain constraints — what reason (aside from idle speculation) do we have for questioning that experience? I look out my window and I see a tree, and while I could play the Descartes game of trying to convince myself that tree does not exist (despite my subjective experience of it), why would I? Likewise, I see myself make a decision — I turn left when I equally well could have turned right — why would I try to convince myself that it was (in fact) not a decision at all. Sometimes there are reasons to question these naïve presumptions (e.g., the sun does not actually 'rise' in the east, and we can prove that to ourselves), but why question an experience without a proper use or reason?

In the Western world, the arguments against free will all stem from an anti-religious, anti-metaphysical worldview. There is a strong reaction in analytic/empiricist circles against organized religion, coming from a strong and bitter historical rivalry. That reaction is extended to metaphysical concepts, like God and the soul, that lie at the heart of religion, and the rejection of 'free will' becomes a tactical assault on those metaphysical concepts: negate free will (so hard-line empiricists believe) and one negates the soul, God, and religion in one fell swoop. But the concept of free will doesn't require a soul, or God, or religion; it is an experience, and metaphysical concepts arise in order to explain that experience, not the other way around.

  • Well, I will disagree with Wittgenstein and others who question on the "use" of the question. For starters, what you point out is a solid reason that this argument is mistakenly used for arguments of "other" philosophies namely analytical/religious. But, this question is of importance because it tells us about how we should think of ourselves. What is the point of doing math? To gain knowledge. What is the point of asking about free will? To gain knowledge. But ultimately, one stumbles upon the question of epistemology. And that is where questions about free will hold weight in discussion.
    – Weezy
    Mar 16, 2020 at 7:01

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