Are We Free?

Try lifting your index finger, freely deciding whether to raise the right one or the left. A second before you make your decision, nothing and no one can predict which finger you will raise, right? So would you think that your freedom had been diminished if you discovered that the outcome of your decision could in fact be predicted before you made your choice?

The study of nature teaches us that, at our scale, nothing happens without a cause, and that in general the world is deterministic, which is to say the future is determined by the state of preceding things. Therefore, a sufficiently precise observation of the state of the world could make it possible to predict even the outcomes of what we regard as free decisions. How can we reconcile this determinism with our experience of freedom of choice? The conflict between the necessity that we observe in nature and our feeling that we have freedom is the basic problem of free will.

The solution to that problem, which I think is the right one, is presented in one of the most beautiful pages of philosophy ever written: the Second Proposition, and its related scoglio, or commentary, in the Third Part of Baruch Spinoza’s Ethics.

According to Spinoza, mind and body are not different entities. They are two ways of describing and conceiving the same entity, and each one is guided by necessity. What do we mean when we say that we make our own ‘free’ decisions? Spinoza’s answer is simple and striking: it means that the outcome of the decision is determined by the complex inner working of our body/mind, and we ignore the complex causes that have led us to make the choice because we are not aware of the complexity of this inner working. ‘Free will’ is the name that we give to those actions of ours the causes of which depend of course on what happens in us, but which we are unaware of. Spinoza observes that the complexity of our body (today we would say of our brain) is very great. If we could know in sufficient detail how it functioned, we would see that, before a ‘free’ decision, there was already in place an unfolding chain of physical events that could have only one outcome.

Today, 350 years later, recent experiments in the field of neuroscience have led to an unexpected confirmation of Spinoza’s idea, opening up a dense and fascinating dialogue between philosophers and neuroscientists.

An experiment in this area was conducted by John-Dylan Haynes at the Bernstein Centre for Computational Neuroscience in Berlin, the results of which have been published in the journal Nature Neuroscience. Haynes used functional magnetic resonance imaging, which is to say a scanner that ‘photographs’ the electrical activity of the brain, in order to observe the cerebral activity of different individuals in the process of making decisions. The subjects of the experiment had to freely decide to push a button on the left, or one on the right. The surprising result is that observation of cerebral activity preceding the moment of decision makes it possible to predict in advance the decision that will be taken. And this prediction can be made as early as several seconds before the actual decision! In other words, while you decide ‘freely’ whether to raise your left or your right finger, the decision is already predetermined, unknown to you, and at least several seconds before you think you are making it, by the biochemistry in your brain. What happens is precisely what Spinoza indicated: the sensation of making a conscious decision appears to be nothing more than a psychological effect, subsequent to the biochemical events which have determined its result. Patrick Haggard, a neuroscientist at University College London, puts it like this in the latest issue of Nature: ‘We think that we are choosing, but in reality we choose nothing.’ I would not put it this way. I would say, rather, that what we call ‘freedom to choose’ is precisely the complex calculation that takes place in our brain. The outcome of a decision depends upon what is in our brain, that is, upon us.

The problems opened up by these experiments have to do not just with neuroscience, but with philosophy and ethics as well. For much contemporary philosophy, the problem of free will is no longer posed in terms of a Cartesian duality between body and mind, according to which the mind acts on the physical reality of the body by means of a special gland in the brain. Many philosophers today have little difficulty in accepting Spinoza’s thesis on free will. But if free will is in this sense illusory, where does that leave individual responsibility? If someone commits a crime without having freely chosen to do so, should we therefore refrain from punishing the crime?

The answer, it seems to me, is obviously not. Using prisons and fines remains an effective practice for society, to defend itself from the actions of the individual in question, and to deter crimes by others, even (in fact, even more so!) in a deterministic world.

The important point, I believe, is the fact that the notion of free will remains useful precisely because we don’t know the microscopic complexity that causes our behaviour. Our behaviour is in fact unpredictable, due to the complexity, as well as to the chaotic and even quantum aspects, of our biochemical make-up. The notion of free will, even if it is an approximate notion based on ignorance of potential causes, remains consequently the most efficacious when thinking about ourselves, just as Spinoza suggested.

But can any of us really accept, even when confronted with the evidence of a machine that foresees in advance which finger we will decide to raise, that our precious free will, if taken literally, is in the end just a sort of illusion? Or are we too attached to our pride as decision-makers, to the rhetoric of the freedom of the spirit, to ever accept such an idea? Spinoza himself, in the Ethics, suggests an answer:

I hesitate to believe that men can be induced to reflect on all of this with equanimity, so firmly persuaded are they that it is only at the bidding of their minds that their body moves or stays still …