The Great Philosophy Event, Tampere, Finland, April 2005
At the start of the twenty-first century, consciousness is said to be
“the last surviving mystery” (Dennett 1991), one of
“the most baffling problems in the science of the mind” (Chalmers 1995). There is nothing we know more intimately than our own conscious minds, and our own stream of conscious experiences, and yet somehow consciousness evades all attempts to understand it scientifically. Why?
I shall argue that the reason is this; evolution has set us up to think about ourselves in a particular way, and this way is fundamentally wrong. Although generally evolution operates to give us accurate ideas about the world, it often has to compromise and cut corners. In the case of ideas about ourselves this process has left us deeply deluded about consciousness and our own minds. If we stay deluded like this we shall never have a good science of consciousness. First we need to understand the many illusions of consciousness and self, then we need to throw them off. Only then will we begin to penetrate the mystery of consciousness.
So, first, what is consciousness?
No one can define consciousness. We all think we know what the word means, but when we try to pin it down it evades us. The closest I can get to a definition is to take the famous question asked in 1974 by philosopher Thomas Nagel. “What is it like to be a bat?”
Nagel argued that consciousness is what makes the mind-body problem intractable, and that we can never know what it is like to be a bat. It is no good me pretending to be a bat by squeaking or hanging upside down. If I really became like a bat I would not be me and would have learnt nothing; if I retained my capacity to speak and think I would not be like a real bat at all. So we are stuck. Even so, said Nagel, thinking about the bat helps us to pin down what we mean by being conscious. If there is something it is like to be the bat then we say that the bat is conscious. If there is nothing it is like to be a bat then the bat is not conscious. This is what we mean by consciousness. It is the “what it’s like to be me.”
Here we immediately hit one of the oldest problems in philosophy – the mind-body problem.
There seem to be two completely different kinds of thing in the world –
Minds and brains –
the inner world and the outer world –
the objective world and subjective experiences –
“what it’s like to be me” and the physical brain which seems to be essential for that “what it’s like”.
This has been called the fathomless abyss, the grand chasm, and the explanatory gap.
People have been trying to cross it for thousands of years and so far they have not, apparently, succeeded.
The latest version of this great chasm arises because we now know so much (though not enough!) about the brain. It’s called the “hard problem”.
In 1994 a young Australian philosopher called David Chalmers coined the phrase “the hard problem”. Put at its simplest it is the question of how physical processes in the brain give rise to subjective experience.
He distinguished between two kinds of problem:
In setting the problem up this way, consciousness is clearly a deep mystery. I am going to argue that we only get into this difficulty because we think about consciousness entirely the wrong way. In other words, I think that consciousness is an illusion. So I must be clear what I mean by the word “illusion”.
An illusion is not something that does not exist – like a ghost, or Father Christmas, or the tooth fairy. An illusion is something that does exist but is not what it seems to be.
The most common examples are visual illusions like this cube. You will probably agree that on the screen there is nothing more than 7 black circles with white lines on them. Yet you see a cube. You even see it in three dimensions and you may be able to flip the cube from one perspective to the other (the central point either coming towards you out of the screen or going away into it) – and there is no cube there!
What can you see here? You know it’s just black and white lines. Can you see colour? Movement? Shapes?
Some people see pink and pale green petals flowing out from the centre. This is an illusion. Something is there but not pink and green petals.
What can you see here? Is the larger man chasing the smaller one? Is the larger one more frightening to look at?
I watched my son and cut and paste the men so I know they are identical. Yet I go on seeing the illusion.
So this explains what I mean by illusion – something that is not what it seems to be. Consciousness, then, is not what it seems to be.
This means we have to start from how it seems and try to work out what goes wrong.
Does being alive feel like this? Please look at this picture and decide whether you feel this way. I don’t mean do you really believe that there is a little person inside your brain pulling the levers, but does it feel as though you are somewhere inside your head, having a stream of consciousness experiences, and able to influence and control your body and the world outside?
Please put up your hands if, for you, it does feel this way. I shall ask the audience to put up their hands and count them.
It feels this way to me a lot of the time. Even though I have spent decades trying to understand the mind, and knowing it can’t be this way, I still often feel as though I am someone inside this head here.
Dan Dennett, the American philosopher, calls this the “Cartesian Theatre”. He argued, in his 1991 book Consciousness Explained, that everybody rejects Cartesian dualism – Descartes’ theory of two separate mental and physical substances – but they still retain important aspects of Descartes’ thinking; they still think about consciousness as though it were a series of events or experiences – a show, happening to someone inside their head. He calls such people “Cartesian materialists” because they claim to be good scientific materialists but still retain the magical idea of a time or place at which brain processes “enter consciousness” or suddenly “become conscious” as though on display to a conscious self. As he says …
“When you discard Cartesian dualism, you really must discard the show that would have gone on in the Cartesian Theatre, and the audience as well, for neither the show nor the audience is to be found in the brain, and the brain is the only real place there is to look for them.” (1991 p 134).
If I open up someone’s brain and look inside, what do I see? I might go to someone in the audience, or ask one to come on stage, and pretend to open up their head. I see millions of neurons with billions of connections between them. There is no middle in the brain; no central place where all the important bits come in for “me” to see them; no command centre from where my orders go out to my muscles and the world beyond. There is just a massively interconnected, parallel processing system. So then where am “I”? And where is the stream of consciousness experiences?
In 1890 the American psychologist William James coined the term “the stream of consciousness” because, he said, consciousness is not chopped up in bits, it flows like a river or a stream. Certainly it feels this way but I think this metaphor is completely misleading – it is another example of Dennett’s Cartesian theatre. The stream of consciousness is the same basic idea as the show going on in the non-existent theatre. It is very tempting but it is the wrong way of thinking about consciousness.
You might think that no one really thinks this way in the twenty-first century but you would be wrong. One of the most popular kinds of theory is called “Global workspace theory”
This assumes that consciousness is like a theatre in which the contents of consciousness are on the stage of working memory, lit up by the spotlight of attention, and watched by an unconscious audience sitting in the dark. The main protagonist of this theory, Bernard Baars, claims that it is not a Cartesian theatre, yet it retains all the central ideas of Cartesian materialism – the show, the display, the stage and the audience.
Other hints of Cartesian materialism are seen in common concepts used in studying consciousness such as “the contents of consciousness”, the “neural correlates of consciousness” or such phrases as “enters consciousness” and “becomes conscious”. All of these imply a “magic difference” between some brain processes that are conscious and others that are not. Many scientists, such as Francis Crick and Christof Koch for example, think of it this way and are trying to find out where in the brain consciousness happens, but I think they can never succeed. We have to start again in the way we think about consciousness.
I shall give some examples that show just how wrong we can be about the contents of our own consciousness.
Do you think that, right now, you have a rich and detailed picture of this hall inside your head?
This is the usual way of thinking about vision that has been assumed by the cognitive science of the past 20 or 30 years. The idea is that when we look around a scene we take in more and more information on each saccade (large eye movements). Then we gradually build up a representation of the scene inside our heads until we can see the whole picture in more or less detail. This picture, or mental representation, is what we consciously see.
This may give you some idea of what I mean ….
Does it seem like this ?
So what’s wrong? Why do I say it cannot be this way?
I’m now going to show you a picture. You will only see it briefly so I want you to look very carefully. Afterwards you can tell me what you saw.
What you saw was an array of 18 identical portraits of Dan Dennett, of which one had horns and a scar.
So what’s wrong? You say you saw these portraits and indeed you were right.
What is wrong is this. When you look at something you can only see the very centre clearly – anything off to the side by even a few degrees is indistinct. So to see one of these portraits clearly and be able to identify it you would have to look straight at it. You were shown the picture for exactly 2 seconds. Most people make 5 or 6 eye movements a second. So in 2 seconds you will have focussed on only 10-12 positions. In fact you probably used up 4 or 5 eye movements exploring the scar and the horns. So you cannot have looked at all the portraits. This means you cannot have a detailed representation in your head of each one.
What you may have is a lot of information and the general idea that there are 18 such identical pictures, rather than a pixel-by-pixel pictorial representation. Or perhaps you have something else altogether. All we can say so far is that there’s something wrong with the traditional theory.
The phenomenon of change blindness gives us more clues.
Imagine you are looking at me and suddenly my hair changes colour from red to green, or perhaps something on the table disappears. Would you notice? Of course you think you would, and probably you’d be right, because your visual system has special detectors that notice sudden changes or movements.
However, if the change happened just as you blinked would you still notice it? Research shows that people think they would, but in fact they do not. This is called change blindness.
Change blindness can be demonstrated in many different ways but the easiest is to keep swapping two slightly different pictures with a brief grey flash in between to mimic a blink or eye movement.
Can you see what is changing?
Can you see what is changing here ?
In this example the picture is moved to mimic an eye movement.
Something very clear and obvious is changing here.
All these examples are fun and surprising but what do they really mean? Most people agree that they challenge our ordinary way of thinking about vision. If you imagined that a rich and detailed picture of the world was built up inside your head and that you could consult it at will to find out what has changed, then you were wrong. However, it is not clear what theory to replace this with.
The main question concerns what information is retained between eye movements. Some people argue that representations are constructed but then thrown away with each eye movement. Some argue that a sketchy version of the picture or a more conceptual representation is stored, but the most extreme interpretation is that of Kevin O’Regan and Alva Noë. They propose a sensorimotor theory of vision in which seeing is a kind of action. We do not see because we have a picture of the world in our head – we see because we actively manipulate the world.
If it were true this theory would completely change the way we have to think about consciousness. Being conscious would amount to doing something, not having something “in” our consciousness.
As we saw in the last example of change blindness, attention can be very important for what you experience. We are now going to try a test of attention.
In a minute you are going to watch some kids playing a ball game. There are two teams, the white and the black, and each has a ball. Your task is to count how many passes of the ball are made between members of the white team. In other words, count how many times the ball passes from one white team member to another.
PLEASE keep very quiet while you are doing this. Do not count aloud, or give any clues to anyone else. If you have done the task before please keep absolutely quiet and do not spoil it for those who haven’t.
I hope you enjoyed being fooled. But what does this mean? It suggests that unless we are actively attending to something we simply do not see it. In fact one way of thinking about vision is like this. When we attend to something we build up what is called an “object file”; a representation of just that object that lasts as long as we keep attending to it. When we switch attention to something else the original just falls back into nothingness and a new object file is created. We never realise this is going on because if we ask ourselves “can I see this?” or “Can I see that?” we can always look and instantly the object appears. We cannot, as it were, look into the darkness of what we are not seeing.
This is like trying to open the fridge very quickly to see whether the light is always on. However fast you open the door you can never catch it out being dark.
Consciousness is like this in an even more profound way. Ask yourself this question…
“Am I conscious now?” I suggest that you can never answer “no”. There is something very very strange about this question. Whenever you ask it the answer is always “yes”. But this doesn’t mean you are always conscious does it ??
Do you believe in free will?
If so you probably believe something like this – that deep down you are some kind of inner self who is consciously in charge of the decisions you make, and the actions your body carries out.
Here’s a simple example. Will you please hold out your arm in front of you. Now, whenever you feel like it – of your own free will – please flex your wrist. Now keep doing this. I want you to do it many times and get a feel for it. Watch yourself making the decision about when to move, and then moving.
Now ask yourself this question. Which comes first?
The conscious decision to move
Brain activity related to the movement?
In the 1980s, neuroscientist Benjamin Libet used just this action as the basis for what are probably the most famous experiments ever done on consciousness. He asked subjects to do exactly what you have just done and then he measured three things. First, he measured the movement using EMG (electromyogram) electrodes on the wrist. Second, he measured the start of brain activity (readiness potential in the motor cortex) using EEG (electroencephalogram) electrodes on the scalp. Third, he measured the time of the conscious will to move. The last is the most difficult, and used a revolving spot on a screen.
We can try it now. Please will you hold out your hand and flex your wrist as before. I am now going to use my hand to mimic the spot. As I turn it round, like the hands of a clock, I want you to shout out where the hand was when you made the decision to move. So please shout out “five” if my hand is at five o’clock, or “twelve” if it’s straight up.
This is what Libet’s subjects had to do. Afterwards he could match up the timings and find out which came first:
The conscious decision to move (will)
Brain activity related to the movement.
Which do you think came first? Note that if you think the conscious will came first, this amounts to magic – an effect of the mind with no corresponding brain effect. If you think the brain effect came first then you should conclude that the conscious will did not really start the process. So which is right?
The results were very clear, and have since been repeated with brain scans and other methods.
The start of brain activity in the motor cortex begins 5-600 milliseconds before the movement actually takes place, but the conscious decision to move occurs only 200 milliseconds before the movement. In other words, the conscious decision to move comes too late to be the cause of the movement.
This result has caused terrible trouble. Hundreds of papers have been written about it – indeed there have been several whole books written about it. In the end no one is quite sure what it means. Libet himself argues that we still have free will because we can consciously intervene to prevent, or veto, actions once their associated brain activity has begun. Dennett argues that the idea of timing conscious decisions is itself nonsense and the results have no implications for free will.
Whatever is the correct interpretation, the results suggest that our normal sense of free will has something wrong with it. Once again we seem to be deluded.
Why? I will end with two questions – why are we so deluded, and can we escape from the delusion?
Why are we so deluded about consciousness? As far as conscious will is concerned, psychologist Dan Wegner has proposed that our illusion of having conscious will is constructed in three easy stages. First we have a thought about an action. Then the action is carried out. Then we (wrongly) conclude that the thought caused the action.
In fact, he says, unconscious brain activity gave rise both to the conscious thought and to the action, and our conclusion was wrong. But it is a useful illusion because it serves to inform us which actions we carried out ourselves and which were done by others. For this reason we pay the price of being technically wrong all the time.
As for me, I am sure that free will is an illusion. I have been convinced of this most of my life, and have worked hard to stop falling for it. Over the years the illusion has gradually weakened and now I would say I no longer get the feeling of free will. Actions happen, decisions are taken, choices are made, but there is no sense that I am consciously doing them. Maybe some of you have had the same experience. If not it probably sounds very strange. I can only assure you that it is possible to live without the illusion of conscious will.
What about the other illusions?
Our genes have given us a powerful tendency to see ourselves and others as agents with intentions, beliefs and desires. This is what psychologists call having a “theory of mind” and Dennett calls “taking the intentional stance”. Furthermore, we simplify by imagining a kind of central inner self from which these intentions and desires emanate. This is useful for getting on in the world, but deeply misleading for thinking about consciousness.
Our memes have given us words and language; in particular the word “I” which tempts us into believing in a single, persisting, inner self.
Is it possible to get out of these illusions? 2500 years ago the Buddha declared that the origin of all human suffering lies in the clinging to a false idea of self, and proposed that meditation could help us to let go. Today a few of the scientists and philosophers who study consciousness are also serious meditation practitioners; they work to change their own consciousness as well as studying it. I have been meditating for over twenty years and I cannot say that the sense of self has entirely gone away – but it has certainly became much less secure. This, I think, makes it easier to be open-minded about the mystery of consciousness and to explore the most counter-intuitive theories.
I have no grand theory of consciousness to offer you. I cannot solve the mystery, but I can say that most of the theories we have so far are hopeless. I conclude that it is the persistent illusions of a self who has free will and a stream of conscious experiences that cause all the trouble. They fuel our dualist intuitions and keep us transfixed by the hard problem and the explanatory gap; and they make consciousness seem completely mysterious and inexplicable.
Our only hope for better theories in the future is to throw off those illusions and escape from the Cartesian theatre for ever.