Mick Hartley

Benjamin Libet, the man who conducted what is possibly the most famous experiment ever on the subject of consciousness, has died at the age of 91. Sue Blackmore has a brief article on him at CiF:

[I]t is for his experiment on free will that he will mostly be remembered. In this experiment he wanted to find the cause of our spontaneous, deliberate actions. Certainly we feel as though we consciously decide to act and then do so. Yet philosophers and scientists for hundreds of years have argued that the brain does not need a magical conscious self to start actions off, and free will must be an illusion. Unlike all the thousands of people who have argued around this point, Libet actually found a way to test it.

He asked subjects in the laboratory to hold out their arm and, whenever they felt like it and of their own free will, to flex their wrist. He then measured three things – the time at which the movement began, the time at which the “readiness potential” in the brain began (signalling the brain starting to organise the coming movement) and then, most tricky of all, the time at which the subject made the decision to move.

This really is tricky because there is, by definition, no physical activity in the brain or anywhere else that corresponds to this. He was trying to measure something purely mental – the free decision, or thought, of wanting to act. Finding a way to do this is probably why the experiment became so famous. What he did was this. He had a spot revolving on a screen, like a clock face, and he asked the subjects to call out where the spot was at the exact moment that they decided to act. In other words, they were, after the fact, making a judgement about where the spot was at the time, and that could be used to accurately time the decision to act.

And his results? They were quite consistent and have since been repeated many times. The brain activity comes first, then the decision to act, and then finally the action itself. Not only does the decision to act happen after the brain is already getting ready to set off the action, but it comes nearly half a second later. It looks as though our conscious decision to act cannot, however strongly it feels that way, be the cause of our actions.

Oh dear! Free will seems to be disproved. But it’s not that simple. Libet himself did further experiments that seemed to show that we may not be able to start actions consciously, but we can veto them once they have begun – saving at least some role for free will. But even that does not end the issue. Literally hundreds of academic articles, and several whole books, have been written about this experiment and how to interpret it. This is why I say it is the most famous experiment on consciousness ever done.

In a way the whole furore is bizarre. Most scientists claim to be materialists. That is, they don’t believe that mind is separate from body, and firmly reject Cartesian dualism. This means they should not be in the least surprised by the results. Of course the brain must start the action off, of course the conscious feeling of having made it happen must be illusory. Yet the results created uproar. I can only think that their materialism is only skin deep, and that even avowed materialists still can’t quite accept the consequences of being a biological machine.

She goes on to describe how Libet himself fully believed in free will – in the power, as it were, of mind over matter – but she disagrees:

I think, and thought then, that free will is entirely illusory.

I wrote about this a few months back – about the problem of free will in the light of Libet’s experiments:

This [Libet’s] result depends on the accurate reporting of the conscious experience of making a decision, which is always going to be unreliable. But then why assume that your free will is always conscious? Yes, you may report that the decision took place, as far as you were aware, after the neurological activity appeared – but what prompted that neurological activity? What else but a decision of yours? Otherwise why doesn’t your arm keep moving all the time, randomly? The cause of your arm moving was your decision to move your arm. The fact that your awareness of that decision follows on from the neurological activity doesn’t change that. All it shows is that (perhaps) a part of your decision-making is pre-conscious, or unconscious. That’s not an uninteresting finding, but it certainly doesn’t show that you have no free will.

That still seems to me the best way around the problem: if Libet’s experiments show anything, they show that our will, our decision-making, isn’t always conscious. That’s a great deal more plausible than to assume that we’re just robots whose sense of free will is an illusion. As for the jibe that scientists’ materialism can only be skin deep if they can’t “accept the consequences of being a biological machine”, that’s to pretend that there’s just no problem of consciousness at all. But there is a problem. Biological machines we may be, but we’re still conscious biological machines. Inseparable from that consciousness is our sense of our free will. Well, at least I can make no sense of consciousness apart from free will. In fact I’d suggest that to deny we possess free will is philosophically incoherent. Sadly I’m not going to argue the point, as my brain’s reached its memetic limits.

It’s interesting that Sue Blackmore is, according to her Wikipedia entry, “an active practitioner of Zen” though “not a Buddhist”. I wonder how much the death of the self – the acceptance that one’s ego is an illusion – which in my no doubt superficial understanding is the goal of Zen Buddhism, is the same as an acceptance that one has no free will. If you could really and truly arrive at that state of mind where you believed – you knew – that you had no free will, would that be nirvana? Would you have cast off the veils of illusion? Or would you be insane?