The article concentrates on Libet’s own experiments showing that unconscious electrical activity in the brain preceded voluntary actions by up to 400ms. This discovery has been widely seized on, although not be Libet himself, as a proof that freewill does not exist and thus as a confirmation of the deterministic paradigm of mainstream neuroscience. The main flaw with these experiments and the conclusions drawn from them is that they focus on the trivial. In Libet’s own experiment the subjects had agreed to flex their wrist at some point, and therefore only the timing of the action constituted a free choice. The point about this is that we all know that we perform a lot of voluntary actions on automatic pilot. We go into a room, and then find we don’t know what we went in for, or we find ourselves walking or driving down the road to the commuter station, when we need to take another road that we only use once or twice a year. However, we would not normally take the view that we did have the freedom to choose not to go to the commuter station at any given point. This would look to apply even more to the large scale decisions in life, such as what university to go to, what career to follow or who to marry. It is hard to demonstrate that the readiness potential for a trivial movement such as flexing the wrist has much relevance to such decisions, although these are just the sort of decisions that one would associate with free will.
Libet does address this question in this article, in order to support the idea that it is satisfactory to base our view of free will on such trivial acts, although his arguments do not appear convincing. He points out that simple systems often inform as to the functioning of more complex ones. That measuring the charge of one electron led to knowing the charge of all electrons. However, the example does not provide a very good analogy for the temporal extension and complexity of the type of decisions that we most associate with goodwill. Libet also points out that readiness potentials have been found to precede more sophisticated activities such as beginning to speak or write. However, actual the action of speaking or writing is not in principle very different from flexing a wrist. The relevant thing for a discussion of freewill is the content of the speech or writing and possible earlier consideration of whether this content should be communicated. Libet accepts that deliberation on whether to do something can continue over an indefinite period, but stresses of the actual action which will be preceded by an RP. However, many people might associate their freewill with the process of deliberation, and not the trivial action of getting up from their chair to implement their decision.
Experiments by Libet and in an earlier period by Kornhuber & Deecke demonstrated that that actions that are perceived as voluntary are preceded by an electrical change in the brain known as a readiness potential (RP). This potential begins on average 550ms before an unplanned act. However, it takes human subjects another 350-400ms to become conscious of the intention to act, leaving only a maximum of 200ms before the actual motor act. The brain process for a conscious act therefore starts before the subject is consciously awareness of it.
In this article, Libet considers the possibility that is favoured by some commentators, to the effect that the conscious veto is itself preceded by an unconscious RP. Libet argues that the veto is a different class of sensation from being aware of an intention to do something, in that it is a control function. He also refers to his own earlier experiments that demonstrate a 400ms difference between a signal reaching the brain, and the subject becoming consciously aware of this (Libet et al 1979) (2). Similarly, the later experiments showed a 400ms delay between the onset of the RP and consciousness of the intention to act. (Libet et al, 1983 and Libet 1985) (3&4). The volitional process is seen as coming into play at this point. Libet proposes that this volitional process is not confined to just the urge to act but could embrace aspects of the brain that might implement a veto. Libet sees the function of free will not as starting a voluntary action, but as deciding whether it should go ahead. The impulses for voluntary action are seen as something that appear spontaneously from the unconscious functioning of the brain.
Tags: conscious will, free won't, freewill, Libet, voluntary action Posted by