Are you sure you’re conscious now?

Workshop – Berlin, 23rd April 2005

The purpose of this workshop is to introduce you to some of the concepts and experiments in the science and philosophy of consciousness. This is difficult!!!

If you think you have simple answers, or your own solution to the problem of consciousness, then you have probably failed to understand just how difficult it is.

I hope that by the end of the workshop you will have more tools for thinking with, but will be more perplexed than you were before !


What is consciousness?


“The most important problem in the biological sciences”  (Searle 1997)
“just about the last surviving mystery” (Dennett 1991)
“the most baffling problems in the science of the mind.” (Chalmers 1995)
“one of the last great mysteries of science.” (Greenfield 2000)

Why? Because of the mind-body problem. Mind-brain, inner-outer, subjective-objective seem to be completely different kinds of thing.

Chalmers defined the “hard problem” as “… the question of how physical processes in the brain give rise to subjective experience.” (Chalmers 1995 p 63).

He contrasted it with the “easy problems” such as perception, learning, or thinking. Many people (e.g. Churchland, Dennett) do not think the hard problem exists.


Exercise 1. Defining Consciousness

Work in pairs.

One person proposes a definition of consciousness.

The other then finds something wrong with it.

Swap over and repeat many times.

Try to work quickly and come up with as many definitions and objections as you can – whether you believe in them or not.

Finally, choose the best definition you have found and write it on the board.

We will discuss the objections you came up with.


There is no generally agreed upon definition. The closest I think we can come is to build on Nagel’s (1974) question “What is it like to be a bat?”.

If there is something it is like to be a bat (something for the bat), then the bat is conscious; otherwise it is not.


Exercise 2. Which things are conscious?

Is there something it is like to be a leaf? Or a slug?

Is there something it is like to be newborn baby, or a dolphin or a computer?

Look at the objects provided and make a list of those you think are conscious.

How did you decide ?

If there is time we will get the person who attributes consciousness to the most things to debate with the person who attributes it to the fewest.

Which do you think are conscious

This relates to the question of how or why consciousness evolved. Did it evolve for a reason? Does it have  function? Could we have evolved without it?

Note that if you say yes, you must think that consciousness is an added extra.

Is it? We can think about this by considering the philosopher’s zombie.


This sort of zombie is defined as a creature that looks, acts and speaks exactly like you or me, but is not conscious. In other words, there is nothing it is like to be a zombie; the zombie has no subjective experiences.

Could a zombie exist ? What do you think?             YES                      NO


Exercise 3. Mary the colour scientist.

This is based on a thought experiment by Frank Jackson (1982)

Mary lives in a future when all brain science is complete. She is a scientist who knows everything there is to know about colour vision, but she has been kept in a black and white room all her life and never actually seen any colours.

When she is finally let out, will she be surprised?

Will she learn something new by actually seeing colours for the first time?

What do you think?


Will she learn something new ?                                  YES                    NO


There have been hundreds of arguments about Mary, although some people believe the whole thought experiment is a waste of time and encourages false intuitions about consciousness.

Is the visual world a grand illusion?

What is an illusion?  Examples of visual illusions.

Dictionary definitions include the following “A false impression or notion”, “Something that deceives or misleads intellectually” (Penguin), “Perception of something objectively existing in such a way as to cause misinterpretation of its actual nature” (Webster)

So if I say that the visual world is an illusion, or consciousness is an illusion, or free will is an illusion, or I am an illusion, I do not mean that these things do not exist, but that they are not what they seem to be.

So how does it seem to be?

Dan Dennett (1991) and the Cartesian Theatre (CT).

“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 can be found in the brain and the brain is the only real place there is to look for them” (Dennett 1991 p134)

Many contemporary theories entail theatres and are probably what Dennett calls Cartesian materialism i.e. materialism that still includes a CT.

e.g. Global workspace theory. The idea of the stream of consciousness (James 1890).


Do you believe that you have a rich and detailed picture of this room inside your head now ?

YES                             NO

This is probably the common assumption of cognitive science for the past 30 years i.e. that vision consists of building up an inner representation of the world.


Multiple Dennetts. You can only see clearly in the small fovea in the centre of the visual field. You could only make up to 10 or 12 saccades (large eye movements) in the 2 seconds given. So you cannot have looked at all the Dennetts. Yet you saw them all, didn’t you?

Change blindness. Several demonstrations show that large changes can be made to scenes without you noticing them. In some cases there is a brief flash to mimic a blink or eye movement. In others the picture moves as it changes.

There are several new theories of vision that attempt to explain what is going on (see

William James said “The attempt at introspective analysis in these cases is in fact like seizing a spinning top to catch its motion, or trying to turn up the gas quickly enough to see how the darkness looks.” (James 1890 p 244). The modern equivalent is looking quickly into the fridge to see whether the light is always on.

This is similar to a very curious fact – whenever you ask “Am I conscious now?” the answer is always “yes”. Why is this? What is it like the rest of the time?

Can we look directly and see whether vision is a grand illusion? Can we begin to experience the world in a way that is truer to how the brain really works?

Can meditation help? Or mindfulness?

A test of attention.

You will see two teams of students throwing balls to each other; one wears white shirts; the other black shirts. Your task is to watch the white team and count how many times they pass the ball. i.e. count how many times the ball goes from one white team member to another. When the video stops I will ask you how many you saw.


Who am I ? Do I have free will ?

When we think about consciousness we think about the person who is conscious. Some people even say that you cannot have experiences without an experiencer.

William James declared that “The universal conscious fact is not ‘feelings and thoughts exist,’ but ‘I think’ and ‘I feel’. No psychology, at any rate, can question the existence of personal selves. The worst a psychology can do is so to interpret the nature of these selves as to rob them of their worth.”  (James 1890 i, p 226)

We seem to be the audience in the CT: The ghost in the machine.

If you could have a new and better body would you like to? We seem to be able to imagine this possibility as though “I” am not my body. But am I?

The self seems to have Unity, Continuity, Subjectivity, Control.

Theories of self.

Why do we have a sense of conscious unity?

Ego Theory

Because all our experiences are had by the same person, or subject of experience.
Each person is a persisting mental entity.

Bundle Theory

Because the experiences are tied together by causal relations such as memory – like a bundle tied up with string. On this view there are no persisting selves distinct from brains and bodies. (Parfit 1987)

The term “bundle” comes from David Hume who famously said “For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe anything but the perception.” (Hume 1739)

His contemporary, Reid, protested “I am not thought, I am not action, I am not feeling: I am something which thinks and acts and feels.”

150 year later James summed up the situation like this: “Some would say that it is a simple active substance, the soul, of which they are then conscious; others, that it is nothing but a fiction, the imaginary being denoted by the pronoun I; and between these extremes of opinion all sorts of intermediaries would be found.” (James 1890 i p 298)


What do you think? Many people say they are intellectually bundle theorists but remain emotionally ego theorists. The next thought experiment may help you to find out.

I am a ………………                        EGO theorist                         BUNDLE theorist


Exercise 4. The teletransporter

Imagine a box with a big button which, when you press it, can transport you anywhere you want to go – and back again. When it does so it reads all the information from every cell in your body, destroying them in the process and rebuilding them exactly the same at the destination.

Would you go? Do not quibble over safety or any other details. This is, after all, a thought experiment, so we are not constrained by reality. The box is 100% safe and reliable. If you won’t go in, this has to be for some other reason than that it might go wrong.


Would you go ?                                  YES                 NO


Split brains. 1950s, operation for very severe epilepsy cut the corpus callosum to prevent seizures spreading. Experiments allow information to be routed to one hemisphere only, and receive answers from one only.

How many conscious selves are there in a split brain patient?


What do you think ?                One,      Two,      Many,      None


Different theories of consciousness give different answers e.g.

Parfit says none (bundle theory).

Popper and Eccles’ dualist theory says one.

Global workspace theory says one.

Crick says none “You’re just a pack of neurons”

Others are more subtle e.g. James’ “The thought itself is the thinker”.

SESMETS “According to Galen Strawson, selves are Subjects of Experience that are Single MEntal Things. Like pearls on a string, one after another.

But what if there is no string that ties successive selves together?

What if selves can be snuffed out at any time, like a candle, and lit again another time?

What do you think now? Does a self have Unity, Continuity, Subjectivity, Control ?


Free will

Do you believe in free will ?

Do you believe you can consciously control your own actions ?

YES                                        NO

Exercise 5. Libet’s experiment.

Hold your arm out in front of you and, whenever you feel like it, of your own free will, flex your wrist.

Now answer the question: which comes first –

  1. The conscious thought or decision to act or
  2. The brain activity that controls the action


Which do you think?                           THOUGHT                BRAIN


Libet measured the time of the action (with EMG), the beginning of the readiness potential in motor cortex (with EEG), and “W” the moment of the decision to act using a revolving spot on a screen.

He found that RP started up to a second before the action whereas “W” came only (on average) 350 msec before the action. In other words the conscious decision came far too late to be the cause of the action.

There have been hundreds of papers and several whole books written about this experiment so we cannot cover the many arguments. At the very least the results make us think more deeply about what we mean by free will.

Wegner’s theory of the illusion of conscious will. We think about an action, then the action happens, so we jump to the (false) conclusion that the thought caused the action.

If free will is an illusion, is it possible to escape the illusion ? I say yes – with practice.

This is one step towards escaping from the CT.


So … who are you? What is consciousness? Are you still sure you’re conscious now?



Baars, B.J. (1988) A Cognitive Theory of Consciousness, Cambridge, Cambridge University Press.

Blackmore, S.J. (2003) Consciousness: An Introduction, London, Hodder & Stoughton and New York, Oxford University Press

Chalmers, D. (1996) The Conscious Mind, Oxford University Press

Churchland, P.S. (2002) Brain-Wise: Studies in Neurophilosophy. Cambridge, MA. MIT Press

Crick, F. (1994) The Astonishing Hypothesis. New York, Scribner’s

Damasio, A. (1999) The Feeling of What Happens: Body, emotion and the making of consciousness. London, Heinemann

Dennett, D.C. (1991) Consciousness Explained. Boston, MA, and London; Little, Brown and Co.

James, W. (1890) The Principles of Psychology, London; MacMillan.

Libet,B. 1985 Unconscious cerebral initiative and the role of conscious will in voluntary action The Behavioral and Brain Sciences 8 529-539 See also the many commentaries in the same issue, 539-566, and BBS 10, 318-321

Nagel, T. (1974) What is it like to be a bat? Philosophical Review 83, 435-450.

Noë, A. (2002) Is the visual world a grand illusion? Thorverton, UK, Imprint Academic

Parfit, D. (1987) Divided minds and the nature of persons. In C. Blakemore and S. Greenfield (Eds) Mindwaves Oxford, Blackwell 19-26

Searle, J. (1998) The Mystery of Consciousness. Granta Books, London and New York.

Shear (1997) Explaining Consciousness – The ‘Hard Problem’. Cambridge, MA, MIT Press

Strawson,G. 1999 The self and the SESMET. Journal of Consciousness Studies  6, 99-135

Wegner, D. (2002) The Illusion of Conscious Will, Cambridge, Mass. MIT Press