Epiphenomenalism is the view that mental events are caused by physical events in the brain, but have no effects upon any physical events.

Many of the challenges to this view revolve around how it reduces us to nothing more than machines and goes against our experience of free will.

But do we actually experience free will? Actions come from decisions which are thoughts. But when do we choose our thoughts? It is not as if there is a basket of thoughts among which we pick one out of. Thoughts, instead, seem to pop out of nowhere as many careful meditators have claimed. Sam Harris argues that the entire concept is incoherent.

Some argue that free will is a fundamental component of experience. But if it was a fundamental component of experience, how could it even be doubted? We may not be able to doubt that we experience, but there is nothing preventing us from doubting that we experience free will. Lastly, it is not hard to imagine conscious experience without free will.

So if free will is not experienced, can this be evidence for epiphenomenalism?

  • Related reading (not an answer): plato.stanford.edu/entries/epiphenomenalism
    – Galen
    Sep 6, 2023 at 4:20
  • Charles Lutwidge Dodgson ... go on. Sep 6, 2023 at 6:30
  • 7
    Why can't you doubt your experience? Optical illusions for example? You can doubt anything whether that is a healthy attitude is a different question.
    – haxor789
    Sep 6, 2023 at 8:18
  • 1
    An optical illusion isn’t you doubting that you experience. It can result in you doubting what the experience may be referring to. You can’t actually doubt that you are experiencing. Doubt itself is a form of experience. Sep 6, 2023 at 20:54
  • 1
    @Stewart I've grappled with that paradigm jump before; not entirely sure anymore how it turned out or how it would solve this situation, since it's been a while. But yeah, I'm vaguely familiar with that line of reasoning. Feel free to email me at my domain you find in my profile. :)
    – deceze
    Sep 8, 2023 at 10:58

8 Answers 8


A better argument against epiphenomenalism is that the human-influenced world becomes much harder to explain without free will. For instance, why would my fingers randomly type out this defense of free will if free will doesn't actually exist? It's too oddly specific of a pattern to be created randomly, so any satisfying argument for epiphenomenalism would have to explain not only it, but all the other oddly specific patterns of behavior my body experiences, and the way those cohere (for instance, driving a car, and stopping at the red lights, or eating at a restaurant, but ordering gluten-free rolls).

The concept that I'm a freely willed agent creating these words is simpler than any explanation that would somehow fake agency. And any such explanation would likely require a willed agent somewhere along the line.

For instance, if I watch a movie, I can get caught up enough in it that I think I'm the main character. I experience his choices as if I were actively making them, but in fact, I'm merely watching them. That is an epiphenomenon. However, that movie still required a writer, a director and an actor to intentionally bring it out about. It did not form itself randomly.

  • 3
    “For instance, why would my fingers randomly type out this defense of consciousness if consciousness doesn't actually exist”. Epiphenomenalism doesn’t state that consciousness doesn’t exist. The rest of your argument amounts to “I can’t imagine consciousness without free will. Therefore consciousness requires free will.” That’s an argument from incredulity. Sep 6, 2023 at 19:56
  • 5
    By this logic the fact that apples fall from trees is evidence that the Earth has free will.
    – slondr
    Sep 7, 2023 at 1:53
  • 3
    If you mean libertarian free will, then that seems to be the much harder (poorly-defined/incoherent) explanation. Because "the neurons in your brain fire so as to send signals to your fingers to move (and those neurons firing is ultimately a result of your biology and environment)" is a far more concrete and evidence-based explanation than an appeal to some vague concept of "free will" with no insight into the mechanisms involved, and no insight into how that interacts with the mechanisms we know influences it.
    – NotThatGuy
    Sep 7, 2023 at 9:59
  • 2
    @ChrisSunami I didn't miss anything. There are billions of years of processes involved in the explanation of why your fingers typed this answer, which is a bit much to detail in a comment. You mentioned "randomly" twice, yet only some of those processes are random. Those processes have independent supporting evidence. Your "simpler" explanation is to not explain anything at all, and to either reject the existence of those billions of years of processes, or to try to insert free will at some undefined point inside that, or to try to fit free will around that somehow.
    – NotThatGuy
    Sep 7, 2023 at 12:01
  • 2
    @ChrisSunami It's hard for me to not feel sorry for you, given that you posted an answer to disagree with something, despite you apparently not understanding what you're disagreeing with on even an elementary level, and you just instead resort to attacking strawman upon strawman, and you try to use personal attacks instead of logical reasoning in response to criticism.
    – NotThatGuy
    Sep 7, 2023 at 12:15

Absolutely free will is experienced. Two psychological manifestations of free will are cognitive dissonance and indecision. The first occurs when I am thinking two contradictory things and have to take responsibility for it. The more general experience, that of indecision, is the ultimate burden of free will. If I can choose, then I have to have a basis to choose. Blonde or brunette? Chocolate or vanilla? Reading philosophy or playing a first-person shooter? For a truly advanced mind, such paralysis by analysis may lead to an existential crisis. Such freedom of will may ultimately lead to embracing absurdism: after all, I'm free to think whatever I want as long I can choose. I should choose by thinking my way through it. I can't help but constantly thinking through it. I can't help but constantly choose anew. My free will is thus a prison.


I think you are very much coming at this from the Harris camp. And yes, he is very much arguing against the existence of free will. And yes, I would say that epiphenomenalism is simply Harris' stance by another name. I don't know whether he's ever used that term or would want to be associated with it, but as an outside observer, the two positions seem to go together quite well.

I think this is pretty much all your question is really, but let me add to this a bit more from my perspective. The free will divide—which is also very apparent in the answers here—is mostly a difference of what angle you look at the problem from, I believe.

If you look at it from "inside the box", then you do exhibit "free will" in the sense that you as a biological entity have a full range of possibilities to choose from at any given time. That is as opposed to a severely constrained entity which may be forced to make certain decisions against its instinct or better knowledge. In this sense, there are enough humans on this planet which do not have "free will", as they're very constrained by circumstances.

You could soften this definition a bit more to define "free will" as merely wanting to make certain decisions, even if you cannot carry them out because of external constraints. In this sense, the most constrained people out there may be the most free-willed of all of us, when they constantly experience the tension between what they want but can't have. I on the other hand could hop on a train right now to the airport and fly to the other side of the world on a whim. Is that "free will"? Or merely thoughtlessly acting on random impulses? Is it more free-willed to resist the urge to do this, because that is the wiser decision?

That is where the different angle comes in: looking at it from "outside the box", these decision making processes are going on inside your head somewhere. Harris and other meditators argue that if you really pay attention to that process, you truly have no idea who is coming up with these questions and who's weighing them and who makes the final decision. It just… happens. When you're thirsty, do you weigh the pros and cons of drinking a cup of water? No, you just act. That's a very innate response, almost a reflex. It's one of the many ingrained behaviours we have which are the reason we're still around today, as opposed to having died off as a species long ago.

Our brains make a lot more complex decisions than this all the time. They're complex enough that given strong enough reasons/neural connections/input, they can even override such innate behaviour as eating and drinking. You can voluntarily starve yourself to death. But only very few people in extreme circumstances ever form these extreme overriding connections that would cause that behaviour. Is that an example of free will? Or just of something having arguably gone haywire in the brain? People throwing themselves off of buildings aren't usually viewed as doing so as an act of free will; rather some mental illness is typically being ascribed to them.

Which is all a long winded way of saying: it's really hard to pin down what supposedly is or isn't "free will" in the first place, so the arguments against free will existing at all are there in my opinion. However, from "inside the box", "free will" is a useful shorthand to explain certain behaviour, which "outside the box" doesn't in fact exist. The divide of opinion on the matter is IMO either a difference of definition, or a lack of having glimpsed "outside the box".

  • "... if you really pay attention to that process, you truly have no idea who is coming up with these questions and who's weighing them and who makes the final decision. It just… happens." Introspection often creates biases. In this particular case, when you are trying to pay attention to your own decision making process, the part of you who is paying attention is not the part of you who is deciding. So the observing part of you will lack a sense of deciding (will not feel like it is deciding), since it is not in fact deciding but observing the part of you that is deciding.
    – Olivier5
    Sep 8, 2023 at 10:25
  • That is an interesting perspective. But then, the part of me that is consciously focusing its attention, the "me" that is observing, my conscience experience, apparently isn't the one making the decision. The decision is made by some part of "me" which "I" am not focussing on at the moment. So… it's not my "free will" making any decision, the decision is being made without my doing by some part of "me".
    – deceze
    Sep 8, 2023 at 10:48
  • It's the "free will" of that part of you making decision A. That part of you paying attention has made its own decision, decision B, which is to pay attention to how decision A is made. But it has not paid attention to its own decision B.
    – Olivier5
    Sep 8, 2023 at 11:01
  • Then it seems to come down to a discrepancy of the term "free will". I would think that only the conscious part of "me" could make "free willed decisions", if anything. If some part of "me" can make decisions without me being consciously aware of it or consciously doing it, then it is an automated process in some sense or another which I'm free to consciously focus on or not. That's "inside the box" free-will to me.
    – deceze
    Sep 8, 2023 at 11:08
  • Personally, I don't like the term "free will", find it ambiguous (other than in legal language where it clearly means "by one's own desire or decision, unforced by others"). In philosophy, I prefer the term "free choice" or even better, "agency". But that's semantics.
    – Olivier5
    Sep 8, 2023 at 11:49

Actions come from decisions which are thoughts

Not necessarily. There are a ton of actions that do not come from conscious thought at all. Like currently I'm breathing without sparing a thought about breathing in and out and I still do it. Also I'm typing and while I think about the ideas, concepts, sentences and words, I spare not a single conscious thought on which keys I should hit on the keyboard, in fact I'm actually typing faster than the time that my mind would take to go through the different letters in those words. I can't even follow the movement of the fingers consciously unless I slow it down significantly. I'm certainly not consciously supervising these processes and with respect to breathing might not even have consciously set them in motion to begin with. It is not my "will" that I perform the bodily functions that keep my body alive like having my heart beat and so on.

I do not object to that and don't interfere with it (most of the time) but those are actions that "I" (the entity comprising body and mind) perform, but that are all "body" and not "mind", it's not "me", the conscious agent supervising the body to write these lines.

The process of doing so might even be controlled by the "brain" though not the "mind", so just because "brain" and "mind" are assumed to occupy the same physical space they do not necessarily refer synonymously to the same concept.

That being said, just because there are lots of actions that I do not perform consciously, there are also a lot of actions that I do perform consciously, like "writing" these lines (not the mechanical, but the thought process).

But when do we choose our thoughts?

Similar problem. Yes and no. There are lots of thoughts that you don't chose, because your body is constantly "perceiving" but your mind isn't constantly "listening" to that, so a lot of thoughts are subroutines coming to the surface of the consciousness, because they've reached a threshold of importance to become "emotions" about which we then develop "thoughts". So we don't choose them our bodies chose them for us. That being said just because you can close your eyes and lets thoughts pop up and fade into obscurity, you still have the ability to hold on to a thought, to concentrate upon it, to query your brain for more perception and data about it, to investigate it's connections, reasons and implications. So just because not every thought is conscious again doesn't mean that none is. And despite the fact that our thoughts are limited by our experiences, our thoughts are still quite free to mix and match everything that we've stored in memory. So that we can technically even imagine things vividly that do not exist and even cannot exist. Like do do you have a problem conceiving thoughts of aliens, monsters, gods, teleportation, time travel and so on? Probably not, have you ever seen them in real life? Probably not. But it's not difficult to combine idk a human or animal shape with the constraints of a horror movie, meaning that it should look scary, so idk sharp and metallic (invokes feelings of getting hurt easily by it)? blood red (invokes feelings of being hurt already or being about to as the threat is still present)? Gooey (also not pleasant and might stick and cause illnesses)? Maybe moldy in color and texture (natural aversion because of rotten food)? Dark (so that you can't make out the details and don't know what's hidden)? Or bright (so that you can't see anything)? Or some Cherenkov effect (that looks both marvelous and scary when you think of it's origin)?

So even if we are no gods that could think of a thing that we can't think about, there's still a lot of freedom and possibility in our thoughts and we can to a degree focus our attention or listen to the static.

Some argue that free will is a fundamental component of experience.

Well yes, experience is conscious experience, you can perceive things subconsciously, but you can't experience them subconsciously otherwise the memory would just a a vague indistinct feeling that you can't really comprehend consciously.

But if it was a fundamental component of experience, how could it even be doubted? [...] We may not be able to doubt that we experience,

You can doubt a lot of things. Like optical illusions and so on can make you doubt your perception and experience, or eating and suddenly feeling less angry might make you doubt your emotion of anger and might make you contemplate where it's coming from rather than directly reacting to it.

But I'm not aware of a way to switch off your mind without switching it off completely. You know you can knock your mind out, with physical force or drugs so that you're in a state of unconsciousness but then "you" don't exist, your body is just vegetating, but as long as you exist you are aware of your existence, right? Like you might not be aware of your body but you're nonetheless aware of your mind. And you can't really step outside of your mind. So can you really question your "self"?

Now the problem is that there is a connection between "me", everything occupying the physical space of my body, "me" the conscious mind that does the thinking, "me" the body that does the action and part of the thoughts and stores the memory, including the brain that is part of the body yet responsible for the technicalities of the mind/body interface and likely host to the mind, which is again me, which is host to an internal simulating unit and a will (to interact with the surrounding world) and if they are all interacting based on physical principles then this should be a human machine that connected inputs to outputs, meaning there is no place for a "me" in that picture, yet I am as certain as nothing else on earth that "I" do posses the ability to both act internally "thinking" and "externally" relatively free, that is constraint by the body, by the laws of nature, by my own experiences, but not in a predetermined way or one where things could only go one way, so for all intents and purposes yes, I would say that I do experience free will. But the thing is if that isn't it and things are predetermined than I could feel differently anyway, but this feeling would be the result of my environment, so for practical purposes it doesn't actually matter.

  • 99.9% of the philosophers who developed a substantial concept of action do not count autonomous activities as actions. In fact, most of them consider intent to be essential for action.
    – Philip Klöcking
    Sep 8, 2023 at 7:05
  • @PhilipKlöcking Makes sense, however are these "actions" that I list autonomous activities just because I do not directly will them? The thing is I could make the decision to interfere with them. For example I can stop breathing (at least for a while). So these are different from mere reflexes, they do happen on their own and I don't pay attention to them right now, but I still want them to happen. So can it be possible to act by willful inaction? Like as soon as you become aware of a trolley problem you're making a decision regardless of whether you will your body to do anything.
    – haxor789
    Sep 8, 2023 at 13:23

"Epiphenomenalism is the view that mental events are caused by physical events in the brain, but have no effects upon any physical events."

Suppose my mental events include figuring out how to checkmate a chess opponent and then I carry out this plan successfully. As a result I win a chess tournament and use my prize money to vacation on a Caribbean isle, where I meet my future wife, with whom I eventually have a child who grows up to be a famous artist who sculptures what soon becomes a famous statue.

Wouldn't that quite obviously show mental events affecting physical events?

  • 1
    It shows that biological processes in your brain—which you have subjectively observed as experience— have caused your hands to move chess pieces in a way that caused you to win the match. For any spectator, you may have just been a mechanical turk. Even assuming that you were conscious during the process, was your consciousness actually the originator of those plans and hand movements, or was it merely along for the ride, observing what the neural connections in your brain did given the input they received?
    – deceze
    Sep 7, 2023 at 4:58

Epiphenomenalism means that mental events don't exist at all. If they don't have any effect upon any physical events, they cannot be observed, there is nothing to experience. Only physical events can be observed and experienced. All mental events, including observation and experiencing, are just responses to physical events

In reality, mental events do exist, they do have an observable effect on people's behaviour.

You have left free will undefined. I am assuming here that by "free will" you mean the ability to choose actions.

We can observe free will (by this definition) in action. Choices are made and their observable consequences can be experienced, suffered or enjoyed.

This does not necessarily mean that we actually make our choices ourselves. It is still possible that our free will is an illusion, a false experience. However, this doesn't remove free will totally, choices are still made with observable consequences. Someone must be able to make them anyway and project this illusion into our minds. A highly improbable scenario, as we have no evidence at all for the existence of such mind-controlling beings.

  • 3
    You are simply incorrect here. For starter’s, epiphenomenalism does not mean that mental events do not exist. Secondly, “observation” itself is a mental event. Sep 6, 2023 at 4:31
  • 1
    How can you say that something exists, if that something does not have any observable physical effects? All abstract ideas exist only as their physical manifestations. Sep 6, 2023 at 7:17
  • 1
    "Someone must be able to make them anyway and project this illusion into our minds." — What you observe in your mind is merely the result of the decisions having been made "mechanically" by your brain. There doesn't need to be a 3rd entity with free will. That's the argument.
    – deceze
    Sep 7, 2023 at 1:58
  • 1
    @Pertti What exactly is a "decision"? Evolutionarily we're all just here because we have adopted behaviours which have caused us to stay alive; as opposed to all the organisms which have failed to do so. Simply, given two choices, the organism tends towards one choice over another. Given a cliff, the organism that tends towards stopping survived, as opposed to the organism that tended towards walking right off it. My choosing salami pizza over pineapple is just the same kind of tendency towards one option, due to the myriad of weights affecting neuronal connections in my brain.
    – deceze
    Sep 7, 2023 at 4:44
  • 2
    @Pertti In the same way, if I decided I wanted salami pizza because someone once gave me some and I really liked it, but hadn't learned what a pizzeria is or what delivery services are because I grew up under a rock, then I wouldn't know how to fulfil my desire either. Much the same way a machine which hasn't been programmed couldn't do it. The only real difference is that we bring our own basic algorithms to learn and desire to stay alive, whereas we haven't really produced any machines yet that can really do so.
    – deceze
    Sep 7, 2023 at 8:30

It is not as if there is a basket of thoughts among which we pick one out of.

Perhaps this is exactly what is going on, but we are not or only dimly aware of what goes into the picking process.

(One helluva preposition-at-the-end construction, though.)

  • Not to put words into anyone's mouth, but as far as I get the argument, free-will proponents state that this "picking out thoughts" is what free will is. Then yes, being only dimly aware of what goes into the picking process would mean that there is no free will. The "basket of thoughts" is anything your brain could conceivably come up with, which is mostly a function of your prior experience and the resulting connections it built. The process by which thoughts come to mind is ultimately mysterious, and something like an "implementation detail" of the brain.
    – deceze
    Sep 7, 2023 at 23:34

Epiphenomenalism is the view that mental events are caused by physical events in the brain, but have no effects upon any physical events.

If brain events can cause mental events, then vice versa is also possible: mental events must be able to cause brain events. The mechanism that goes from brain events to mental events is a physical mechanism, and hence it must obey the law of reaction. It cannot work only one way, it must work both ways. Epiphenomenalism makes no logical sense, therefore.

Note that nobody can point at anything that would demonstrably be an epiphenomenon. Such things simply do not exist.

And as pointed out by @PerttiRuismäki, if epiphenomena existed, nobody would know about them, by definition...

The concept of epiphenomenon is an oxymoron. It's like saying: "I can touch you but you cannot touch me".

  • 4
    I don't understand the premise that an arbitrary cause-effect pair can be reversed such that the effect is actually the cause. It is simply not true that if A can cause B, B must logically be able to cause A. Sep 6, 2023 at 19:10
  • 1
    Some processes are only reversible by turning back time, since entropy only goes one way and prevents the exact restoration of a previous state.
    – deceze
    Sep 7, 2023 at 6:14
  • 1
    @Olivier5 Atomic fusion has the same problem as entropy, that is during fission you release energy that dissipates randomly while the reverse process would thus require that you'd concentrate energy in addition to the split products, which is not going to happen on it's own. Though why do you focus on the exact process to begin with? Like if you watch a movie and that makes you feel something, then you're feeling isn't going to influence the movie, but it may very well influence your decision making in the real world. So it can have an effect without being a direct reversal of the process.
    – haxor789
    Sep 7, 2023 at 10:03
  • 1
    @Olivier5 Physical processes are not theoretical concepts. In practice, there is no such thing as a reversible process. Newton's third law does not address causation in any way and is entirely irrelevant. It is rather silly to argue that if pushing a domino causes it to fall over, that the domino falling over can cause you to push it. Temporally, effects must come after causes, it is nonsense to say that an event was caused by something that hasn't even happened yet. Sep 7, 2023 at 13:08
  • 1
    @Olivier5 But the domino example is a pretty clear case where "A causes B" doesnt mean "B causes A", when you define A as pushing the dominoes, and B as the domino stack falling over. Therefore you cant take it as a general rule. It's not even clear how you are trying to fit touching and pushing a domino or vice versa into A and B. Like, the cause and effect are just different in those cases. Touching the domino causes a push on it. The opposite of that would be "pushing the domino causes it to be touched", which typically isn't how we would talk about the cause and effect there.
    – JMac
    Sep 7, 2023 at 22:00

You must log in to answer this question.

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