In the study into free will, I've heard many people use the word "illusion" to describe free will. I think their reasoning is that since all matter behaves according to the rules of physics, people don't really have a choice in their action, and therefore the free will is just a feeling, an illusion or a mirage.

This line of thought is bewildering to me, given our knowledge of physics, and how we gradually learned that concepts that were once thought objective are actually subjective. For example, according to the special theory of relativity, two observers might disagree about the order of two events: For the first observer, event A happened before event B, while for the second observer, B happened before A. None of the two observers are suffering illusions. None of them are more correct than the other. They are both correct from their own point of view.

This is isn't easily grasped the first time you hear it, but it's been an undisputed fact for the last 100 years.

If we can accept that different observers might have such different perspectives, without using the term illusion, why is there a need to say that free will is an illusion? Can't we just say it's a different perspective, same as we do for physics?

  • 2
    Different definitions of simultaneity are just a consequence of using different coordinate systems to denote the selfsame physical events--there is no disagreement about the questions physicists would consider truly "physical", like the amount of proper time that elapses on a given observer's worldliness between two events on that worldline. Are you suggesting that "free will" could somehow be a matter of different coordinate systems for describing the same events? What type of coordinate system would that be, if not a spacetime coordinate system?
    – Hypnosifl
    Commented Mar 15, 2022 at 19:45
  • Yes, I am. Of course, it wouldn't be a "coordinate system" in the Euclidean sense of the world. "Frame of reference" or "perspective" might be better names. I don't have a model built out for that.
    – Ram Rachum
    Commented Mar 15, 2022 at 19:48
  • what relationship is there between general relativity and the chemical reactions in a brain ? Physicists can explain very clearly how 2 observers can come to reach different conclusions about the chronicity of events. Nobody so far has come close to explain why only the chemistry of our brain would defy the laws of nature by happening according to our will (heck, nobody has even be able to define clearly what "our will" would be and how it would exerts itself).
    – armand
    Commented Mar 15, 2022 at 23:49
  • There are many variants of incompatibilism. In some, the term "illusion" might be more fitting, in others "subjective fact". Without knowing which one specifically is talked about, it cannot be decided which word fits better.
    – tkruse
    Commented Mar 16, 2022 at 0:50

4 Answers 4


1.) In the end of your question you ask whether one can solve the clash between

  • our feeling of having free will

  • and the causally closed worldview of physics

in the same way as the former problem of the observer dependent time order: Just taking it as a subjective effect depending on the choice of the frame of reference?

2.) I don’t expect that a solution for the mind-body problem exists at the cheap price of an analogy.

The insight that the time order of two events depends on the frame of reference follows as a result from an ingenious theory, the theory of special relativity. But in neuroscience we still do not have an elaborated theory about the mind-body interaction.

3.) Anyhow we have a well-posed research program:

Reconcile the first-person viewpoint and the third-person viewpoint: Each person feels free, but our scientific theories operate on the basis of determinism.

The problem of current research is to explain the generation of our conscious self-model (first-person viewpoint) on the basis of neuroscience (third-person viewpoint), hence as a result of information processing in the brain.

For a survey from neuroscience see

James A. Reggia: The rise of machine consciousness: Studying consciousness with computational models. Neural Networks 44 (2013) 112–131 (I can send you a copy on request.)

4.) Aside: I do not consider the indeterminism discovered on the micro-level of quantum mechanics to be relevant for explanations on the meso-cosmic level of mental processes.

  • Determinsitc macro scale systems can demonstrate chaotic behavior; therefore microscale indeterminacy can be amplified up to the macro scale through chaos. Your point 4 is therefore clearly untrue. Point 3 -- is considered untrue by almost all scientists, who have found exclusive reductionism to be a failed research program outside of physics, about half of chemistry, and the subfield of biochemistry within biology. See the SEP article on scientific reduction. Points 1 and 2 look fine.
    – Dcleve
    Commented Mar 16, 2022 at 7:27
  • @Dcleve ad 4) Could you please name a reference which shows: Quantum mechanical indeterminism explains phenomena observed at information processing in the brain? Penrose's ideas on this issue did not convince me. - ad 3) What about the survey of Reggia? Which passage from the SEP article - I assume the section on philosophy of mind? - contradicts the research program from neuroscience?
    – Jo Wehler
    Commented Mar 16, 2022 at 7:56
  • Section 5 of the SEP article notes that reductionism is now mostly abandoned in philosophy of science. The characteristics taht lead to a failure of reduction are when the concepts of interest in a higher tier are radically orthogonal to the terms of the substrate. The details of atomic behavior are of no relevance to, say, population dynamics, or whether a new ecological niche is available for species adaptation. The concepts of population biology -- individuals, populations, ecosystems, niches, etc are simply incompatible with physics reduction.
    – Dcleve
    Commented Mar 16, 2022 at 8:16
  • Other reduction failure markers include the complexity of the phenomenon being investigated. Consciousness is a VERY complex phenomenon, and its parameters of interest are radically orthogonal to the structure of neurons, hence the plausibility of neuroscience providing a 4th new area where reduction actually works -- are vanishingly small. For an example of the sorts of failures it is experiencing, see this article nautil.us/an-existential-crisis-in-neuroscience-8735/…
    – Dcleve
    Commented Mar 16, 2022 at 8:20
  • A chaotic neural system amplifying quantum mechanical indeterminacy would allow brains to be easily influenced by negligible energy inputs, proving a ready path for dualist interaction where weak psycho-influence could steer brains.
    – Dcleve
    Commented Mar 16, 2022 at 8:27

In the physical world it appears that all known phenomena are deterministic. At a Newtonian level we see objects following Newton’s laws, and even at the quantum level we see that things we can’t predict follow statistical patterns, which strongly suggests there’s an underlying deterministic principle that we don’t know about. If we believe that consciousness is a part of the physical world then our actions must also be predictable to an observer who has infinitely precise information and unlimited computing power, and of course knows how to extrapolate future events from past events. If this is the case then although one might think that they are making a choice of their own volition, it is in fact a predetermined choice, and so it could be said that this is an illusion because the subject thinks that their choice isn’t predetermined. On the other hand, the subject may be comfortable with the idea that the choice could have been known in advance, but they made it themselves anyway.


Philosophy has known the difference between illusions and "difference of perspectives" for far longer than relativity theory is known.

As witnessed e.g. by the https://en.wikipedia.org/wiki/Blind_men_and_an_elephant parable with the earliest writings dated 500 BCE.

So your introduction of theory of relativity has no value for the discussion, at all.

Philosophers will choose the word "illusion" when they mean "illusion", and they will use the word "different perspective" when they mean that.

There are diverse incompatibilist views about free will, and without knowing which one you refer to it is impossible to go into details about whether the word "illusion" fits better than other classifications. However there are definitely some models and interpretations where the term "illusion" is much more fitting than "different perspective".

Copying from wikipedia:

In his book Free Will, philosopher and neuroscientist Sam Harris argues that free will is an illusion, stating that "thoughts and intentions emerge from background causes of which we are unaware and over which we exert no conscious control."

People typically experience a thought that is consistent with a behavior, and then they observe themselves performing this behavior. As a result, people infer that their thoughts must have caused the observed behavior. However, Wegner has been able to manipulate people's thoughts and behaviors so as to conform to or violate the two requirements for causal inference.[197][198] Through such work, Wegner has been able to show that people often experience conscious will over behaviors that they have not, in fact, caused – and conversely, that people can be led to experience a lack of will over behaviors they did cause.

  • "there are definitely some models and interpretations where the term "illusion" is much more fitting than "different perspective"": Can you share one, and hopefully explain why "different perspective" doesn't work there?
    – Ram Rachum
    Commented Mar 16, 2022 at 9:47

The idea of free will as an illusion is not a serious one worth of any deeper discussion. It is only a half-wit half-idea for a party trick.

Nobody has ever properly thought what it would actually mean. An illusion is a misinterpreted observation. Nobody has ever explained what is happening in reality while we experience this illusion, what would be a correct interpretation.

If making your own decisions is an illusion, then who is making the decisions in reality? How is this illusion projected into the minds of outside observers? If you see someone making a choice, how can you experience the same illusion? Who is making these illusions, for what purpose?

Free will is not an illusion, it is the ability to decide what you do. Your decisions control the physical actions of your muscles.

There is no concept of control in physics. You might say that your decisions cause the physical actions of your muscles, but that would not be entirely accurate. In a philosophical sense, yes, your decisions insert new causes in the causal flow of events. In a physical sense your muscle actions are caused by burning of glucose converting chemical energy to kinetic energy. Your ndecisions only control which muscles do it and when.

  • "The idea of free will as an illusion is not a serious one worth of any deeper discussion" I'm ignorant about the field. Are there any highly-respected philosophers who use the term "illusion" for free will? Or any of them who specifically rule it out?
    – Ram Rachum
    Commented Mar 15, 2022 at 18:42
  • 3
    “ Nobody has ever properly thought what it would actually mean” - that’s quite a claim.
    – Frog
    Commented Mar 15, 2022 at 19:14
  • 4
    I strongly encourage you to treat this answer with skepticism. If you want to get a grounding in the different perspectives of free will and come to a more informed decision about both free will and how your 2nd paragraph need not impact upon whether or not free will is illusory, check out SEP's Free Will, Causal Determinism, and Compatibilism. Many believe that there is far more evidence against free will than for it. Commented Mar 15, 2022 at 19:59
  • This answer shows a complete lack of knowledge about the field it pretends to cover, as well as a complete lack of logical coherence ("there is no concept of control in physics", but "your decisions control"...). Sure, Spinoza and all the philosophers he influenced are complete amateurs that can just be dismissed with the back of the hand.
    – armand
    Commented Mar 15, 2022 at 23:57
  • The question is not about whether free will is an illusion, but whether it should be called an illusion assuming it was not true. This answer might be valid for a different question, but is off-topic here.
    – tkruse
    Commented Mar 16, 2022 at 0:46

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