A free-will experiment

Say you can detect my body preparing to move before I’m conscious of my decision to move it, and you take it to prove that I have no free choice. If you’re right, you should be able to tell me when I was going to move without affecting the outcome. If my consciousness is not a cause of the what happens, nothing should change by making me conscious of what will happen.

So how about we run that experiment. Hook a bunch of persons who are convinced that they have free choice* up to an apparatus and tell them we’ll hit a light every time we know they will move. I predict the persons can give you any set of compliance/non-compliance ratios you want. And what would that tell us?

Notice that this is different from Libet’s “free-won’t” experiment, because there is nothing in it that says you have to not move when the light says you will. If you want a compliance/ non-compliance rate of .5, the guy you hook up can ask for 15 trials and comply on five. You could even ask for a total compliance ratio – but what would it mean to get it?

*We have to pick these sorts of people because otherwise our peers could critique any positive results by saying that the participants chose to give us the results we were looking for out of solidarity with us to prove free choice is a sham. Oh wait…



  1. February 21, 2016 at 5:03 pm

    You can in fact do an experiment like that where a light turns on when the apparatus determines that they are going to move, before they actually start moving, but late enough that it is too late for them not to move at all (although they will still be able to interrupt the movement part of the way through, if they want to.)

    In any case, that has nothing to do with free will one way or another. Consciousness that we have made a choice is posterior by nature to the choice itself, not prior, no matter what choice consists in.

    • February 21, 2016 at 8:28 pm

      Are you saying this experiment has been done? I haven’t seen that anywhere. Given the set-up I described, where a person is deciding before hand how he’s going to react to the indicator light, I find your description dubious (or at best, an experiment that takes advantage of the relative slowness of reaction speed to the light. Libet said he could call the motion a half-second in advance).

      I also can’t quite tell whether you concede or avoid the main point: Remember, the whole point of the post was that if the causality of conscious thought really is being denied, then the light ought to have no effect at all.

      • February 21, 2016 at 8:53 pm

        Yes, the experiment was done not that long ago: http://www.pnas.org/content/113/4/1080.full.pdf

        I agree that this is a question of reaction times but do not see how this is relevant to your argument.

        If your main point is that the conscious idea of “I am going to do X” is the cause of my doing X, then I do indeed disagree with that. Rather, my decision to do X causes both my awareness of my decision and the fact that I do it. St. Thomas would say the same thing: the thought “I am going to do X” is a conscious reflection on the act of the will, and the act of the will is therefore prior by nature to that reflection.

      • February 21, 2016 at 10:35 pm

        Thanks for the link, but I don’t see how it is anything more than a test of reaction times. But apparently that point is moot on this thread.

        the act of the will is therefore prior by nature to that reflection.

        But causal priority is not temporal priority, which latter is the only sort of priority the experiment measures. There is also a causal but not temporal priority between what I hit and what gets hit, which is also an act of reflection.

        That said, you aren’t saying that all choices are made unconsciously and only become conscious by reflection, or that consciousness plays no causal role in choice, so I don’t get what your angle is in all this. Is it that the experiment measured only reflections on choices, and confused reflective choices with all conscious choices?

  2. vishmehr24 said,

    February 22, 2016 at 5:39 am

    “the act of the will is therefore prior by nature to that reflection.”

    Should the movement be properly called an act of the will?
    Isn’t the case that freely willed acts are defined to those that follow the intellectural deliberation.?

    • February 22, 2016 at 6:52 am

      He’s distinguishing “I want x” from “I am aware that I want x”, and the first can be deliberate without being reflective while the second just is reflective. With the further, very reasonable stipulation that you can’t think two thoughts at the same time, we’d also introduce some time lag between them.

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