Functionalism views the mental processes in terms of causes and effects (ex. inputs such as sensory stimuli and output such as moving an extremity).

But how would free will fit into this theory if at all?

One would imagine that he has at least some control over his thoughts. If a person would like to think about ice cream, for example, then he would be able to by the power of his free will. Wouldn't the decision of thinking about ice cream be a mental process itself?

If it is, then the output is obvious, but there must be some input that caused the output. If the output (thinking about ice cream) is really dependent on some input, then how could free will exist?

What I mean is this: It seems that any array of possible actions performed via the power of free must be at least somewhat restricted by some input(s). Environmental factors influence our behavior, such as seeing a family member or intoxication. So, some input(s) should restrict the possible actions one can choose to do, but there is always some range of outputs that can be chosen from if there really is free will. It is important that:

  • There are multiple outputs that can be chosen from (if there was only one then these input(s) would not allow for free will).
  • An agent of free will can choose which of these outputs to "pick."

The action of "picking" (like "picking" to think about ice cream) seems to be a mental process as well, however. It must also be viewed in terms of input(s)/output(s) in the view of functionalism. So, in the action of "picking," what would be the input that causes one to "pick"? And if there really was this sort of input and output, then how could "picking" be an action of free will?

Let's say that there are some input(s) that similarly restrict what one can "pick," but not completely so free will can be allowed for. Even if this is the case, how can "picking" the available outputs be explained in terms of functionalism? It seems that the process of "picking" some available outputs would still require an input until there is only one available output.

It consequently seems that functionalism does not allow for free will. Am I wrong or correct?

Source of my views on functionalism: Internet Encyclopedia of Philosophy's Article on Functionalism

  • Do you have a source for your views on functionalism? This would help put the question into context. One could always say that if functionalism does not allow for free will then functionalism has been falsified. Aug 9, 2018 at 22:38
  • @FrankHubeny Yes, from iep.utm.edu/functism/#H2 , "The functions in question are usually taken to be those that mediate between stimulus (and psychological) inputs and behavioral (and psychological) outputs. Hilary Putnam’s contribution was to model these functions using the contemporary idea of computing machines and programs, where the program of the machine fixes how it mediates between its inputs and standing states, on one hand, and outputs and other standing states, on the other."
    – MacroGuy
    Aug 11, 2018 at 21:33
  • @FrankHubeny Also, why should it be assumed that a theory that does not allow for free will should be falsified? Why assume free will does not exist?
    – MacroGuy
    Aug 12, 2018 at 0:39
  • It's a different perspective. I don't know if functionalism allows for free will or not. However, if it turns out that it does not then those who assume we have free will can use that to claim that functionalism is false preferring to keep free will over functionalism. Aug 12, 2018 at 0:57

5 Answers 5


I think that we "get in trouble" when we think that some of these theories are "mutually exclusive" instead of thinking one is good at explaining a portion of our selves and another is good at explaining some other portion. Together, they can explain more than each individually! Let me give an actual example:

It was a hot evening and as I was watching TV, I was getting thirsty. I starter thinking about getting up, going to the refrigerator, and pouring myself some cold tea. However, before I got up, I remembered that there was ice cream in the freezer, so when I got to the refrigerator, I got ice cream instead.

This example shows that for this action, there was not only a "cause & effect," but also "free will" got involved.

Using the analogy of a plane, functionalism would be the auto-pilot, and free will, the human pilot. Just like the human pilot decides to engage or disengage the auto-pilot, free will also decides when to allow functionalism to take, or not, control of a given situation/action.

  • I think that makes functionalism and free will very compatible if that is the case! Interesting!
    – MacroGuy
    Aug 14, 2018 at 22:00

I agree with functionalism and I agree with free will. The way that I rationalize this is with the analogy to quantum mechanics. You can measure the speed of a particle with precision, but not its position. You can also measure position with high precision, but not if you are measuring its velocity. With the mind you can break open the skull and look at every nerve ending to establish the cause of all stimulation, but you will not see free will. It's only when the brain is isolated from observation like a black box does free will emerge due to the concerted reactions of many many complex reactions that we cannot predict from stimuli and reaction alone.

  • Why should an inability to "observe" free will in action mean that it exists? I would also like to further argue that we are not able to anticipate the complex reactions within a brain due to our lack of knowledge. If every physical detail of the body was known (reaction mechanisms, incoming stimuli, etc.), would we be able to predict the future actions of a person? If not, then it may suggest that free will is something that operates beyond the physical world. Why should material things be able to decide how it reacts to the world? How can that be described in terms of functionalism?
    – MacroGuy
    Aug 14, 2018 at 21:56
  • Hmmm. I didn't say that "we can't observe free will". I said that functionalism and free will probably can be both be observed, but not at the same time hence the analogy. "If every physical detail..." Probably not. We may have the same brains but my neural networks are different than youra because we have our own memories so it is still a complicated process.
    – Cell
    Aug 14, 2018 at 22:56
  • "Operates beyond physical world" Not necessarily. For example systems of equations can be entirely physical but their chaotic nature can make it difficult to predict their future behaviour.
    – Cell
    Aug 14, 2018 at 23:04
  • Even so, their future behavior (despite being chaotic) is determined by physical causes. The system is not deciding what its output is like a human being with free will; its output is caused by initial factors even though these factors are too complicated or unknown to us. Free will would not be a good analogy to these chaotic systems since some conscious entity can determine its output (or do what it won't do). Any initial factors (even if they are too complicated or unknown to us) would restrict that action of a human being and not allow for free will even if the relationship iscomplex
    – MacroGuy
    Aug 15, 2018 at 4:57

Does functionalism of the mind allow for free will?

  • Guill said, "However, before I got up, I remembered that there was ice cream in the freezer, so when I got to the refrigerator, I got ice cream instead."

It is probably the memory function of the mind that actually allows the capacity for free will, because it provides the basis for decision making. People with faulty or weak recall tend to make poor decisions and have great difficulty learning from mistakes. Free will is a survival mechanism.

  • That doesn't explain how free will and functionalism could be compatible. It could be argued that the memory function of the mind serves to provide input for future outputs (deciding to get ice cream due to the input of the memory of ice cream in the freezer). Also, why should free will be a survival mechanism? Wouldn't philosophical zombies that are "programmed" to react appropriately to their environment via natural selection be able to survive? Why is free will necessary?
    – MacroGuy
    Aug 14, 2018 at 22:02

Does functionalism of the mind allow for free will?

Functionalism is the view that the mind is the function that a physical realizer plays.

A physical realizer can be a human brain, computer chip, Martian organ. But in the case of functionalism, they all perform the same task, they take input and provide output.

Machine functionalism is a special type of functionalism which views the mind as a Turing machine.

A Turing machine is symbol manipulator machine, which takes input, writes (or erases)it as symbols on a memory tape, and all of this happens according to a set of instruction called the machine table. The machine table breaks down a complex problem into small tasks, and these small tasks or states are called machine states.

Machine states are seen as mental states in machine functionalism.

But here is the problem. In Machine functionalism, the inputs are sensory inputs, and outputs are motor outputs.

And on this view, the brain is not literally the Turing machine, it is the functional mechanism that is the Turing machine.

But what is the ontological relationship between the physical realizer and Turing machine?

Surely, Physical Realizer takes input and provides the output, but the Turing machine does the computation the result of which is mental states.

But what does it compute?

Theories of representation argue that the sensory inputs are codified into representational contents. But representational contents have semantic properties and syntactic properties. But the Turing machine can only manipulate syntactic properties of the symbol.

Then, functionalism cannot explain how semantic properties of content are manipulated.

Now functionalism claims that mental state can cause other mental state or physical actions. In other words, it is causally efficacious.

But this claim seems to be false, because if semantic properties of symbols are not manipulated, then the Turing machine cannot provide intentional outcomes. And if it cannot provide intentional outcomes, then it cannot causally affect the physical world.

Thus the idea is that if the core premises of functionalism are true then the mind takes input and computes them but it cannot really provide an output, since providing output requires semantic manipulation of representational content.

The result of the computation is various mental states but the output is null. In other words, it leads to epiphenomenalism. Epiphenomenalists argue that the physical world is causally closed and that the mental states are an epiphenomenon of various physiological activities. In that sense, functionalism implies that we do not have free will.


Let us say you feel pain when I pinch you. The input is pinching, and the function is feeling pain. The output is wincing, but this has nothing to do with your feeling pain, it is just your body physical body reacting to physical stimuli, that is pinching. Then according to functionalism, we do not have free will.

Obviously there is something wrong with functionalism, and it can be illustrated in myriad other ways.

For Further Reading:

Block, N. (1989) “Can the mind change the world?” In Boolos, G.S. (ed.) Meaning and Method: Essays in Honor of Hilary Putnam. Cambridge University Press. pp. 137--170.

Fodor, J.A. (1974) Special sciences (or: The disunity of science as a working hypothesis). Synthese, 28 (2): 97–115.

Kim, J. (1992) Multiple realization and the metaphysics of reduction. Philosophy and Phenomenological Research, 52 (1): 1–26.

Kim, J. (1998) Mind in a Physical World: An Essay on the Mind-Body Problem and Mental Causation. MIT Press.

Kim, J. (2011) Philosophy of mind [electronic resource] / Jaegwon Kim. 3rd ed. Boulder, CO: Boulder, CO : Westview Press.

Lewis, D. (1970) An argument for the identity theory. Journal of Philosophy, 63 (2): 17–25.


Freewill is a monumentally huge topic, which does not have one clean definition which is sufficient to answer your questions. You have to choose definition to move forward.

One definition I find very useful is to define freewill as an action which occurred at least in part because of the internal state of the entity which is not known outside of the entity. This sort of black box (or even grey box) definition provides a natural way for freewill and functionalism to coexist until you start considering omniscient entities -- but freewill gets murky there anyways.

The usual counter is that you aren't "free" because you can only do what your state tells you to. And that's reasonable, for some definitions of freewill. Then the question becomes "do you have the freewill to do what you wont do?" And it becomes a fun discussion.

  • I agree that your definition of free will allows free will and functionalism to co-exist. I think that having the ability to do what we won't do, however, is not very compatible with functionalism unless there is some ability for functionalism to somehow be "deactivated" allowing for manual control by a conscious entity.
    – MacroGuy
    Aug 14, 2018 at 22:08
  • @MacroGuy The fun discussion I find is whether the idea of having the freedom to do what you won't do is compatible with whatever other definition of freewill that is brought to the table. I find it focuses the exploration and discussion on the new idea.
    – Cort Ammon
    Aug 15, 2018 at 1:49

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