I’m in a discussion with “The Thinker” concerning the mental, the physical, and causality (among other things). Though a self-described naturalist, The Thinker appears open to the possibility that there is an immaterial mind (he failed to provide an account of how matter can exhibit inherent intentionality). However, he believes that the physical (brain) always causes the mental and that the mental never causes the physical.
As evidence for this belief he linked to a paper entitled Tracking the Unconscious Generation of Free Decisions Using Ultra-High Field fMRI by Stefan Bode, Anna Hanxi He, Chun Siong Soon, Robert Trampel, Robert Turner, and John-Dylan Haynes. In short, subjects were in an fMRI machine and told to click a left or right button and record when they were consciously aware of which button they were going to click. The researchers studied the fMRI data and were able to decode the brain activity taken seconds before the subject was consciously aware of what button he was going to click to predict, with up to 57% accuracy, the button that was, in fact, clicked.
Since I’m no neuroscientist, take my comments on the article with a grain of salt. But I don’t think this study warrants the conclusion that the physical always causes the mental and that the mental never causes the physical.
(1) The researchers claim that the subjects “were free to decide, at any time, to press the left or the right button with the corresponding index finger.” In fact, subjects that did not behave in certain ways were excluded from the study. “[I]t should be obvious that moving a finger that one was requested to move is no less voluntary an act than is moving one or another of two fingers on request” (Bennett and Hacker, Philosophical Foundations of Neuroscience, p. 231).
“If one asks one’s subjects to move their hand voluntarily within the next minute, but to take care to note when they feel an urge, an intention or a desire to move it, one’s very question subjects them to a tempting (but mistaken) philosophical picture of the nature of action and its causal genesis. Indeed, one of the most interesting (inadvertent) results of these experiments is that people, when asked to report such bizarre things as ‘a feeling of intention to move one’s hand’, will find such a feeling to report, even though it is more than a little doubtful whether there is any such thing as ‘a feeling of intention’. Equally, when asked to note when they feel an urge to move, they come up with such a feeling, even though moving one’s hand voluntarily does not require and does not normally involve any such feeling. The feeling reported is not what makes their movement voluntary, and any absence of feeling would not make it involuntary. The fact that the neurons . . . fire . . . before the feeling is allegedly apprehended does not show that the brain ‘unconsciously decided’ to move before the agent did. It merely shows that the neuronal processes that activate the muscles began before the time at which the agent report a ‘feeling of desire’ or ‘feeling an urge to move’ to have occurred. But, to repeat, a voluntary movement is not a movement caused by a felt urge, any more than to refrain voluntarily from moving is to feel an urge not to move which prevents one from moving” (Bennett and Hacker, Philosophical Foundations of Neuroscience, p. 230).
So, such an experiment is not studying free will or voluntary action. It seems to involve a gray area between voluntary action and involuntary action, perhaps called non-voluntary action. It is not the kind of case where we would necessarily expect the mental to cause the physical.
(2) “Chance level for correct prediction was 50%.” The researchers were able to decode the fMRI with an accuracy up to 57%. You claim that the physical always causes the mental and the mental never causes the physical. What do you make of the 43% of cases where prediction was not possible? Could that be when the mental causes the physical?
(3) The researchers state “early predictive activity patterns are attributable to unconscious components of evolving intentions.” How do you rule out the possibility that unconscious mental states caused unconscious physical states which caused conscious mental states?
(4) The researchers say “data from one trial cannot be used to predict the trial preceding or following it.” Your position states that the causality effecting the fMRI is all on the physical level. Thus, whatever caused the subject to click a button in trial 1 should be causally connected to what caused the subject to click a button in trial 2, should it not? Why isn’t this observable?
(5) The researchers note “that our study cannot provide evidence for a causal relationship between the activation in frontopolar cortex and the decision, e.g. because fMRI measures neural decision-related processes only indirectly and prediction is far from perfect.” How are you not guilty of misusing the science in this study?