Free will’s win
The work of the late Benjamin Libet, which produced evidence that our decisions to act are made nonconsciously, have thrown up genuinely new challenges to the reality of free will, there is no reason to conclude that it demonstrates free will to be an illusion.
There is a widespread feeling among scientists and scientifically educated members of the public that science has eliminated or is about to eliminate free will and moral responsibility.
Writing in the Proceedings of the National Academy of Sciences in 2010, Anthony Cashmore spoke for many when he claimed that “as more attention is given to the mechanisms that govern human behaviour, it will increasingly be seen that the concept of free will is an illusion”.
The distinguished evolutionary biologist Richard Dawkins draws what he sees as the obvious conclusion, writing that “a truly scientific, mechanistic view of the nervous system make nonsense of the very idea of responsibility”.
Whether gleefully or regretfully, these writers speak for many: free will and moral responsibility are unscientific, and we had better get used to living without them.
There are two claims to which these scientists appeal in making the case for the non-existence of free will and moral responsibility, both of which depend on the uncontroversial idea that human actions depend on the brain. The first claim is that the brain is a deterministic system. The second claim is that contemporary neuroscience shows that actions are caused by the brain and not by the person.
The first argument goes like this. Free will requires that we have the ability to choose between alternative courses of action. Do I spend my tax return on a flat screen TV or donate the money to Oxfam? Do I go for a jog or lie in bed? If I can do only one of these things and not the other, then I do not freely choose which I do.
But if the brain is deterministic, then we never have the ability to make such free choices, because determinism is the thesis that every event – including brain events – is made necessary by the preceding events. Therefore, we have no free will.
This argument is very frequently advanced by scientists triumphantly announcing that they have solved the age-old problem of free will. Few things annoy philosophers more.
This is not because all philosophers think the argument is fallacious. In fact, opinion is deeply divided on the validity of the argument.
What annoys philosophers is the fact that the scientists who make this announcement think that they think they are telling us exciting news. In fact, philosophers have been debating whether determinism is compatible with free will for many centuries. In the light of this debate, the scientists’ pronouncements look nothing short of naïve.
The second claim is far more interesting, and genuinely new. It stems from work of the late Benjamin Libet. Libet asked subjects in his experiments to move their hand whenever they felt the urge. He also asked them to note the position of a dot travelling around the face of a specially constructed clock when they felt the urge. People are able to do this with surprising accuracy. Libet also timed the readiness potential – a surge of electrical activity in the brain known to precede voluntary action – in his subjects’ brains. The finding which has attracted so much attention was this: the readiness potential occurred a few hundred milliseconds prior to the person becoming aware of the urge to move. Libet concluded that nonconscious mechanisms in the brain made the decision to move and only once it was already under way did the person become aware of it. Because of this evidence that our decisions to act are made nonconsciously, many neuroscientists argue that they are not free.
This argument is genuinely new, and backed up by data. Neuroscientists and philosophers alike have found in Libet’s work, and the work of other scientists who have built on it, a powerful challenge to the reality of free will. I think this is a mistake. Though I do not question the scientific importance of Libet’s work, I do not think that there is any reason to think that it shows that free will is an illusion.
In fact, Libet’s work is neither surprising nor threatening.
It is not surprising because we ought to expect that brain events precede consciousness of the occurrence of these events. Signals take time to be transmitted across the brain, and therefore we ought to expect that the consciousness of a decision will lag slightly behind the brain events that constitute these decisions.
But there is no threat here because there is no reason for us to want to be conscious of these decisions instantly. What we want is that our decisions be properly responsive to our attitudes – our beliefs, desires, values, and so on – and to our deliberations.
Nothing in Libet’s work suggests that this is not the case. So there is no special need to worry about these results.
Nor need we worry about more recent results, for instance those of leading neuroscientist C S Soon and colleagues in a 2008 paper “Unconscious determinants of free decisions in the human brain” (Nature Neuroscience 11:543-5), which extended the gap between brain events predictive of a decision and the making of the decision to a massive six seconds.
Again, this isn’t surprising. In ordinary language, we speak of people having inclinations one way or another. We don’t think that these inclinations are chosen, or that people are necessarily aware of them.
These brain events may be the neural correlates of inclinations, or desires, or preferences. Soon and colleagues found that these events predicted the subsequent decision with about 60 per cent accuracy. This, too, is unsurprising and unthreatening: we should not be surprised that people usually choose in accordance with their inclinations.
Neuroscience is a rapidly developing field, and it is constantly providing us with better data and theories concerning how humans act.
Some of this data helps us to understand how and why we all too often lose control and find ourselves acting in ways that we come to regret: consuming addictive drugs, overeating, or lashing out violently, for instance. This data may well help us to understand how free will works and how it can be lost.
But nothing it has produced so far and nothing it is likely to produce will show that we never have free will at all.
Neil Levy is Head of Neuroethics at the Florey Neuroscience Institutes and honorary Associate Professor in the Department of Philosophy at the University of Melbourne.