A few years ago, Benjamin Libet conducted a series of experiments on the experience of choosing and deciding. While brain and nerve impulses were being monitored, subjects were asked to make some trivial choice – e.g., to move a finger up or down and to report the moment of decision-making. What Libet found is that the nerve impulse from the brain to the finger was on its way before subjects reported having made the choice. Now, the difference is not much – on the order of half a second – but since nerve impulses propagate at finite maximum speeds, once the impulse to move the finger one way or the other is on the way, it appears that no later decision can derail it nor can the finger’s movement depend upon the later decision. (Libet actually thinks this is not quite right, but it’s not important to go into for the present.)
This seems deeply at odds with lived experience. Try it for yourself. Hold out your hand and, after a short interval, decide whether to move it left or right, or else up or down. Pay attention to what goes on, to the decision as it is experienced. Do you believe – can you believe – that your hand did not move in response to your choice? Nonetheless, that seems to be the conclusion to which Libet’s evidence points.
What to make of this? The face-value interpretation is that the experienced choice is some sort of illusion: it occurs after, and therefore cannot affect, the generation of the nerve impulse that causes the finger movement. If anything, the conscious, experienced choice is some kind of epiphenomenon, a reflection in experience of some underlying process, and it is the underlying process, not the decision, that accounts for the way the finger moves and perhaps also for the way the decision is experienced. If we generalize this, we get the disturbing thought that our actions never depend on our conscious reasoning or decision-making.
We might find a bit of wiggle-room in the fact that it is the reported conscious choice that doesn’t stand in the right time-relation to the movement-causing nerve impulse. Since the face-value interpretation requires that something is distorting introspective access to what’s going on when we choose and act, face-value interpreters cannot, on the basis of some supposed introspective reliability, object to the suggestion that the distortion might be in the apparent timing of the choice rather than in the dependence of the action upon the choice.
But let’s leave this aside. Suppose Libet’s evidence does show that the “choice” has no effect on which way the finger moves. Must that upset our notions of freedom and responsibility? Not obviously. For Libet’s evidence does not bear at all upon what must surely be the most common and prominent cases in which we think our actions depend upon our choices. For the choice to move a finger a minute hence is notably trivial, and more, it is notably arbitrary in that it is hard to see how there could be a reason for moving it this way or that. What, though, about a choice today to act in a certain way tomorrow? Nothing Libet has shown indicates that tomorrow’s actions cannot depend upon today’s choice. If there are reasons to be concerned that our lives are not under our own control, that the disturbing thought is true, they are not to be found in Libet’s work.