Dr Gregory Farrelly FAITH Magazine November – December 2012
1. In an experiment in the early 1980s, Benjamin Libet used electroencephalography (EEG) to record the brain activity of volunteers who had been told to make a spontaneous movement. They were asked to note the time they became aware of the urge to act. The EEG recordings revealed a signal, the "readiness potential", occurring about 550 milliseconds before the movement and the awareness of the urge to move.
This seemed to contradict the traditional view of free will and mental causation as it indicated that our awareness of the will to act (in this case to move a finger, etc) occurs after the brain has decided to act - suggesting that our self-consciousness regarding free will is, in fact, mistaken. The brain acts before the mind decides!
In August New Scientist reported that Aaron Schurger, leading a research team in France, had tested the assumption that the readiness potential is the signature of the brain preparing to act. Previous studies indicated that when a decision is based on visual input, for example, assemblies of neurons start accumulating visual evidence in favour of the possible outcomes, a decision being triggered when the evidence favouring one outcome crosses a threshold. Schurger's team hypothesised that something similar happened in the brain during the Libet experiment. However, Libet's volunteers were asked to ignore any external information before moving, so any trigger to act must have been internal.
Neural activity fluctuates randomly in the brain as "noise", and Schurger reasoned that movement is triggered when this "noise" reaches a threshold. In a computer model, a decision to move was signified whenever the noise crossed a threshold. When the model was run repeatedly, the pattern of neural noise before the decision appeared as a readiness potential. Next, the team repeated Libet's experiment, but this time if the volunteers heard a click, they had to act immediately. The researchers predicted that the fastest response to the click would be seen in those in whom the accumulation of neural noise had neared the threshold before the click, showing as a readiness potential in their EEG graphs. This is precisely what they found. As Schurger says: "...what looks like a pre-consciousdecision process may not reflect a decision at all. It only looks that way because of the nature of spontaneous brain activity."
2. It is important that as informed Catholics we take note of scientific discoveries, yet as Catholics we believe that the truths of science can never be in contradiction to the author of those truths, namely God. There is certainly a strongly held view, exemplified by popular scientists such as Steven Pinker, professor of psychology at Harvard and an avowed atheist, that there is no such thing as free will in the sense of an independent personal entity. In his view, and that of the predominant "physicalist" philosophy of mind school, our physical behaviour is the product, in the natural way of things, of purely physical processes in the brain rather than of some mysterious soul.
As so often in issues discussed in this column, there is a problem here as regards metaphysics, or the lack of it. Modern philosophy, in abandoning metaphysics, has seen the construction of differing views of the contrast between free will and determinism. Dualists believe there are two separate but interacting dimensions within the human person: soul (or mind) and brain. Monists deny a separate soul, saying that everything is matter. Those who think free will is compatible with a deterministic, monist view are called compatibilists. Dominant among neurobiologists and philosophers, they make a distinction between constraints that are external and those that are internal (ie determined by the material brain). In their view, free will simply means being able to follow one's own desiresand preferences.
At the heart of the matter is causality. Is free will nothing more than a human feeling of freedom when a neurological analysis would show this to be illusory? Or is there a real faculty of personal choice? Certainly, the legal system, building upon the universal human experience of responsibility, assumes the latter.
Invoking a neurological instance of Godel's incompleteness theorem, that a system is never self-explanatory but requires some causal explanation from outside, we need to state that the physical causal closure of the human being is an unjustified physicalist assumption. We regard free will as involving a personal judgement rather than one determined by physical nature, however complex the nexus of stimuli and neurological impulses in the brain. If not, what is it that enables us to push beyond any specific environmental niche, to act beyond what is materially determined, for example to fast despite being hungry? What material law of being could result in such behaviour, unknown in other animals which, like all materials things, are defined within the limits of specific ecosystems?
There is a growing school of thought in the philosophy of mind which denies that physical closure has been proved (cf Thomas Pink's Free Will: A Very Short Introduction, OUP). The compatibilist view of free will is insufficient since it assumes that the human mind is completely determined by the material environment. As Edward Holloway described, the material development of free will in an animal is impossible since all matter is subject to the law of control and direction, ie determined, and thus environmentally circumscribed.
If free will is metaphysically real, the human mind must be an exception to the law of material control and direction. In this view, matter in the brain is substantially relative to spirit as its co-principle of determination. The soul (spirit) is the principle of self-consciousness, of personhood. In the words of the Catechism: "Endowed with a spiritual soul, with intellect and with free will, the human person is from his very conception ordered to God and destined for eternal beatitude" (n.1711).