Regardless of whether the mental is ultimately physical or not... doesn't the impact of human knowledge (science, mathematics, etc) on the world (ie: technology, agriculture, basically everything), give us proof that the mental affects the physical?

Ideas like epiphenomenalism or psycho-physical parallelism seem ridiculous to me, because they would imply there's no causal link from the mental events leading to knowledge... to the building of bridges, cars, particle accelerators etc... ie: These ideas imply knowledge does not affect the world (ie: our knowledge of the Pythagorean theorem has no impact on whether things get built properly).

On a more trivial level, they would also imply that when I act on a piece of information my knowledge of the information has no impact on my actions afterwards. eg: I learn the location of a restaurant and I'm able to drive up to where it is located. But if the mental does not affect the physical then my knowledge of the location of the restaurant had nothing to do with the fact that I arrived there.

  • 1
    I asked a similar question a few months ago, and didn't get any answers. I suppose the jury is out on this one. philosophy.stackexchange.com/questions/29876/… Commented Feb 25, 2016 at 6:08
  • 1
    @AlexanderSKing, yes you're basically asking the same question. I think this argument against epiphenomenalism (conceptual knowledge is mental which clearly affects the physical), is a more powerful argument than talking about mental events like "desires" or "willing". Commented Feb 25, 2016 at 6:15
  • It's not enough, I suppose for some, to posit or demonstrate a link; when the link is non-specific and abstract, as in a non-constructive existential proof in mathematics; some, I suppose want every detail spelled out. Commented Feb 25, 2016 at 12:10
  • Epiphenomenalism and parallelism do not in any way presume no effect of the mental on the physical at the granularity where the rest of your post speaks. If the mental is an expression of the physical, then the physical it espresses has effects on the other physical, and that is an effect of the mental on the physical as far as the analysis here goes. Obviously when I speak my mentation is having physical effects in the vague terms you are speaking in. Don't put up straw men.
    – user9166
    Commented Aug 17, 2016 at 19:38
  • 1
    Likewise, if matter is psycho-physical then you have a false dichotomy.
    – user20253
    Commented Oct 5, 2017 at 11:10

8 Answers 8


The threat of epiphenomenalism is indeed a major issue intensively discussed in the last decades. But while there is a broad consensus against it, there is no agreement as to what exactly blocks it. Burge in Foundations of Mind (Ch. 20) even says that the dominance of materialism in the contemporary philosophy of mind is a reaction (in his view unwarranted) to the epiphenomenalism anxiety. The simplest resolution would be physicalism, mental states are reducible to physical states, then of course there is no problem with them affecting the physical. So far physicalism was unsuccessful in reducing even classical chemistry to quantum mechanics (in fairness, the problem is incredibly complex for technical reasons), and with reducing mental to physical the added difficulty is understanding what that even means for qualia, consciousness, volition, etc. Physicalism still has many supporters, but its popularity somewhat waned.

With that non-reductive materialism and dualism gained in popularity, but there the problem manifests itself in the form of causal exclusion argument articulated by Kim. First, it is widely believed that microphysical states (of the brain in particular) are causally complete, i.e. what happens to electrons, etc., depends only on their quantum state. This does not necessarily mean determinism, the point is that nothing other than their physical state at time t can influence their physical state at later times. Even that may not determine it fully, but causally completeness excludes any additional co-determiners. Since physical effects can not be caused twice over the state of the brain can not also be affected by “mental states”, whatever they are, unless they identically reduce to something physical. Thus, there is no top down causation from mental to physical, and mental has no physical influence. Just like images on TV screen have no causal influence on the physical state of the TV, even if we can often predict what will happen next in a movie from them alone.

Some materialists, and causal dualists, do reject causal completeness of the microphysical, e.g. the Stanford Disunity Mafia (this is a nickname for a group of analytic philosophers which includes Dupré, Hacking, Suppes and Nancy Cartwright). Dupré in Metaphysical Disorder and Scientific Disunity argues that it as a hasty generalization from toy examples in tightly controlled laboratory conditions, which are far removed from either brain’s environment or complexity. This blocks the causal exclusion argument, but a plausible account of top down causation has not yet been offered any more than a physical reduction. Penrose's speculations about quantum gravity causing collapse in the brain microtubules are quite fantastic, and Kauffman's explanation that "mind does not act causally on brain at all, rather it acausally decohers to classicity (for all practical purposes), hence has consequences for brain and body as matter" is rather obscure. In principle, top down causation might even be consistent with some future version of physicalism, but that would seem to require developments in physics far beyond our current state of the art. See also Top-down Causation without Top-down Causes by Bechtel and Carver for a deflationary view of top down causation consistent with traditional physicalism.

The middle path between reduction and top down causation is supervenience, the idea that mental changes "track" physical changes, but do not collapse into them. The idea originated in Davidson's Mental Events (1970), and Yablo (1993) and Bennett (2003) gave (what looked like) promising constructions of the tracking. In them the mental is so intimately related to certain physical aspects that bringing about one necessarily brings about the other. So one could say that when knowledge, etc., affects our actions we are strictly speaking referring to its physical companion, but the difference is technical as the two are inextricably linked. Unfortunately, these constructions of tracking were recently shown not to work, see Exclusion, still not Tracted by Keaton and Polger (2014). But the general approach remains attractive to non-reductive materialists.

The intuition against epiphenomenalism is strong and widely shared. The problem is not that people doubt that information should make a physical impact somehow, but that no one can explain how.

  • 1
    I agree that assuming causal completeness over the microphysical is way too premature. But we also have quantum indeterminacy. ie: quantum laws don't explain completely what happens physically. Couldn't the mental impinge on the physical through quantum "choices" which have no physical explanation. Either way, imo there's a lot of room for substance dualism. Commented Feb 25, 2016 at 21:07
  • There is also a more modern take on physicalism which is non-reductive, i.e. eliminative materialism.
    – Era
    Commented Feb 25, 2016 at 22:28
  • @Ameet Sharma Quantum mechanics as currently understood implies causal completeness despite indeterminism, quantum evolution is not fully determined by initial state, but nothing else contributes causally either. Top down causation does not necessarily imply dualism (Dupré is a materialist), but it is unclear how it might function here (e.g. how mind "tells" electrons which slits to path through), while reproducing the ironclad probabilistic predictions. I added a bit on Penrose's and Kauffman's suggestions.
    – Conifold
    Commented Feb 25, 2016 at 23:10
  • @Era Yes, Dupré and Bennett belong to this tradition, reduction is replaced by a weaker notion of supervenience of mental on the physical. In this view the main challenge is to explain how supervenience is implemented, and either describe how it underwrites the mental/physical aspects, or reconcile it with top down causation.
    – Conifold
    Commented Feb 26, 2016 at 0:07
  • 1
    If mental states are not causally effective, how can our talking about them really refer to them?
    – viuser
    Commented Sep 18, 2016 at 2:41

One could simply argue that human knowledge is reducible to the physical, and then there's no causal problem. The serious problem for all theories of mind, I think, is the so-called hard problem of consciousness, since even if everything is given causal explanation, there's still something missing, that is, the experience of consciousness.


If I understand epiphenominalism correctly, it basically assumes that the mind, the "mental" is able to gather information from the physical being (neurons and such) but is not actually able to influence it in turn. Basically like the ghost stories where ghosts roam the world, able to watch and go through walls but not able to change anything and not being noticeable by physical creatures.

Since, according to Heisenberg, nothing can be observed or measured without altering it, which would imply influence, epiphenominalism would therefore violate that principle.

If one sticks to Heisenberg and believes that it should not be violated, then either the mind can "Read AND Write" the physical side, or it can do neither.

Which brings it back to the mind-body problem which asks exactly that question - whether a mind/mental/soul exists and if so, how does it interact with the physical world.

  • Thank you for the effort of rewriting your answer! I'm cleaning up my comments here as they are obsolete now. If you need any more help with the site, check the help center or our support & discussion site, Philosophy Meta.
    – user2953
    Commented Aug 17, 2016 at 9:29

I think the impact of human knowledge on the world as a proof to causal influence on mind to matter can be attacked by an epiphenomenalist in the following way:

Information and knowledge stored in the brain have (obviously) a physical nature, the brain - like a computer memory - always changes his physical structure to store data and then it can send data to other brains. This works according to mechanical laws of physics. We have also machines who learn, collect and send data to other machines, they also can have huge impact to the environment, yet there is nothing mental in them.

  • 1
    I don't think this works. In an epiphenomenalist worldview, it is not knowledge that is stored physically. Knowledge is a mental experiential thing so from an epiphenomenalist viewpoint, it has no causal influence on the physical world. There is some parallel physical process going on that does the causality in the physical world, but knowledge cannot be involved. Commented Feb 28, 2016 at 18:10
  • What if we just speak of information storage and transfer? Commented Feb 28, 2016 at 18:29

I think you are missing the point of epiphenominalism, or I don't understand it, or I misunderstood you.

As I understand it, epiphenomenalism means that our phenomenal experiences are caused by nothing and therefore cause nothing. Nothing causes phenomenal experiences or consciousness, and consciousness cannot cause anything. The world is "causally closed" meaning that the physical can only effect the physical.

Physical causes are "un-grounded", meaning they happen for no reason and there is no first cause. The example you gave of humans causing changes in the world are not physical. They can be traced back to the intentions of a person and therefore are "grounded".

I think your objection to phenomenalism would go away if you did not confuse these two different meanings of the word "cause". For example, a person can decide to do something and "cause" their limbs to move as an action, but they can't "cause" their body to rotate around the earth or move through space. Causes of the first type are considered "epiphenonmenon" since they are concurrent with physical causes but have no effect on them.

It is just useful to use the "intentional idiom" as causes because it allows for better prediction of human behavior. Physical causes, however, are not limited to human actions and behavior.

  • 1
    So according to epiphenomenalism, mental events don't cause physical events right? ie: an engineer's knowledge of the pythagorean theorem has no impact on his ability to build anything. Commented Apr 12, 2016 at 17:25
  • no, that seems absurd. if you asked what caused this building to be built you could answer that engineer did it, although it sounds kind of unnatural.
    – user20502
    Commented Apr 12, 2016 at 17:38

I think epiphenomenalism is dismissed a bit too easily in much of this discussion. The reason is that what epiphenomenalists mean by "mental" isn't necessarily the common interpretation of the word. For example, some of them will consider qualia to be mental, but beliefs (as they are stored in the brain) not mental in the relevant sense. Clearly beliefs influence the physical world -- I believe that no car is coming, so I cross the street -- but that doesn't cause a problem for this type of epiphenomenalist, because the belief (as stored in my brain) is physical. The link on epiphenomenalism above has more discussion.

What I consider to be the key problem for epiphenomenalism is that when we speak and write about mental events such as qualia, those are physical events as well, resulting in sound waves and books and the like. This seems to commit the epiphenomenalist to a view that all that discussion about mental events (mental in the epiphenomenalist's sense!) is not actually influenced by those mental events at all, and so cannot really be about those mental events. This seems to be a bizarre position to hold and rather fatal to the view. I would be interested in ways around this conclusion...


There is no doubt that the "mental" affects the "physical"!
I planed and built a tree-house for my grand children, and now a tree (a physical thing) has been affected by my plan (a mental process). However, non-mental processes (micro-organisms) can (and do) affect the physical, as well.

  • This doesn't really address the philosophical problem highlighted in the OP.
    – user2953
    Commented Aug 16, 2016 at 17:31
  • Yes, that was exactly the question.
    – viuser
    Commented Sep 18, 2016 at 2:41

Of course there is a causal influence of the mental on the physical. To claim otherwise would be absurd.

Let's examine this absurd counterfactual: If the mental processes had no influence on the physical world, they would not be observable, as only physical events and objects are observable. We do not have any kind of telepathy or extra-sensory perception.

Unobservable things do not exist. Minds do exist. Minds do cause observable events. Minds are capable of communication through physical media.

You must log in to answer this question.

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