When I seem to decide to move my arm, is it my “mental decision” causing this, or is the “mental decision” simply an after effect, a signature of sort in consciousness that occurs after physical reactions within my brain?

Is this an empirical question? What does science have to say about this based on our research?

  • 1
    On a reflex movement, I didn't think the movement but science knows that comes from the nervous system. Does ‘mental’ means ‘voluntary’?
    – tac
    Jul 26 at 18:22
  • 1
    those aren't even exhaustive. what if the mental decision came first but didn't cause it?
    – user66760
    Jul 26 at 18:32
  • 1
    what even do you mean by "mental decision"? you are bad at philosophy
    – user66760
    Jul 26 at 18:38
  • 1
    @AgentSmith are you drunk? I didn't understand one single word of what you said
    – tac
    Jul 26 at 19:00
  • 1
    @AgentSmith What is a ‘sun in the boxing ring’? There is one sun, not 40
    – tac
    Jul 26 at 19:18

5 Answers 5


Causation is something we infer, through empirical reasoning. When I am taking a math test, and see a math problem, then solve it, it is reasonable to infer that the reason I solved it, was my desire and intention to solve it. If I have a thought I want to share, then speak or write about it -- likewise, a mental event is reasonably inferred as causing a physical event. there are multiple examples we all experience every day in just navigating our lives -- the feeling of hunger, plus images of a sandwich, lead my feet to walk me to the kitchen.

The only reason that anyone questions this very evident fact about our world, is because of an ideology -- that of physicalism.

But the various physicalist alternative "explanations" of the only "apparent" relationship between mental events and physical events, have all been shown to violate one test case or another. And in general, they require some otherwise unknown and unevidenced force or relationship to tie the mental to some unknown and more central physical process, which is then postulated as the "real" cause of both the mental event, and the apparent physical response to it.

Our world IS a complex place, and there are a lot of subtle and non-intuitive features to it. That the mental COULD be derivative off the physical, and only "apparently" rather than actually causal, is certainly a possible outcome of investigation. But the "hard problem of consciousness" is that none of these physicalist explanations that have been proposed to date both pass all our test data about consciousness (See Blackmore's A Very Short Introduction to Consciousness for multiple failed test cases for physicalist speculations), AND would then lead to our being conscious. elaborating on this second point: in almost all cases for these physicalist speculations, the consequence of evolutionary variance acting on a non-causal consciousness would lead to consciousness disappearing.

The "hard problem of consciousness" is that these physicalist speculations are less straightforward than just accepting the causality of thoughts, they contradict observations we have from consciousness studies, and they do not explain why we have consciousness at all.

Note, contrary to Blackmore, there are possible "physicalist" explanations if one allows for causal emergent consciousness to be a feature of the physical. This would involve accepting that thoughts really are causal.


I would not say that the decision causes the arm movement. A decision is not a physical event. We can trace back the causes to the burning of glucose in the muscles. The presence of glucose and oxygen are caused by the blood flow and your eating and breathing.

But it is a verifiable fact that your decision determines which muscles you move and when. We can say that your body causes the muscle movements but your mind controls them.


We can do the sciency thing and work from the following statement: moon('s gravity) is the cause of ocean tides. That's a really good zero as far as I can tell.


As you phrase it in the title of the question, it seems to basically be the question of whether epiphenomenalism is true, which as described in that article is

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

You can find various arguments against epiphenomenalism in that article; I find the self-stultification argument described there convincing, specifically (since pain is a mental event)

suppose S is an epiphenomenalist, and that S utters “I am in terrible pain.” S is committed to the view that the pain does not cause the utterance. But then, it seems, S would be making the same utterance whether or not a pain were occurring.

On the other hand, as you phrase it in the body of the question, it seems to be closer to an experimental question; for that, see for example this paper, whose abstract states

Free will is a perception that people have that they choose to make their movements. This perception includes a sense of willing the movement and self-agency that they are responsible for the movement. If there is a "free will force" that plays a role in movement selection, it should precede movement. There is no evidence for a driving force, and the perception of willing is not fully processed until after the movement.


I'm new here, looks exiting!

I would start from the principle of action-reaction: to all action, there's a reaction. This implies that epiphenomenalism is false: the causal link between biological events and mental events cannot be uni-directional. It must run both ways: biology has mental effects and vice versa. Otherwise the principle of reaction would be violated. Thus, thoughts are causal, like anything else.

Nothing in this universe is a mere effect, without being also potentially a cause. There can be no dead end to causality.

Intuitively, if there can be a cause-to-effect relationship from A to B, then the same mechanism can be used in reverse, to create a cause-to-effect relationship from B to A.

Hope this makes sense.

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