Consciousness

Consciousness is widely viewed as the last frontier of science. Modern science may have split the atom and solved the mystery of life, but it has yet to explain the source of conscious feelings. Eminent thinkers from many areas of science are turning to this problem, and a wide range of theories are currently on offer. Yet sceptics doubt whether consciousness can be tamed by conventional scientific techniques, and others whether its mysteries can be understood at all.

What is Consciousness?

The best way to begin is with examples rather than definitions. Imagine the difference between having a tooth drilled without a local anaesthetic and having it drilled with one. The difference is that the anaesthetic removes the conscious pain ... assuming the anaesthetic works!

Again, think of the difference between having your eyes open and having them shut. When you shut your eyes, what disappears is your conscious visual experience.

Sometime consciousness is explained as the difference between being awake and being asleep. But this is not quite right. Dreams are conscious too. They are sequences of conscious experiences, even if these experiences are normally less coherent than waking experiences. Indeed, dream experiences, especially in nightmares or fantasies, can consciously be very intense, despite their lack of coherence - or sometimes because of this lack. Consciousness is what we lose when we fall into a dreamless sleep or undergo a total anaesthetic.

The Indefinability of Consciousness

The reason for starting with examples rather than definitions is that no objective, scientific explanation seems able to capture the essence of consciousness.

For example, suppose we try to define consciousness in terms of some characteristic psychological role that all conscious states play - in influencing decisions, perhaps, or in conveying information about our surroundings.

Or we might try to pick out conscious states directly in physical terms, as involving the presence of certain kinds of chemicals in the brain, say.

Any such attempted objective definition seems to leave out the essential ingredient. Such definitions fail to explain why conscious states feel a certain way.

Couldn't we in principle build a robot which satisfied any such scientific definition, but which had no real feelings?

Imaging a computer-brained robot whose internal states register "information" about the world and influence the robot's "decisions". Such design specifications alone don't seem to guarantee that the robot will have any real feelings.

The lights may be on, but is anyone at home? The same point applies even if we specify precise chemical and physical ingredients for making the robot.

Why should an android become conscious, just because it is made of one kind of material rather than another?

There is something ineffable about the felt nature of consciousness. We can point to this subjective element with the help of examples. But it seems to escape any attempt at objective definition.

Louis Armstrong (some say it was Fats Waller) was once asked to define jazz.

Man, if you gotta ask, you're never gonna know.

We can say the same about attempts to define consciousness. ...

The rest of the book gives a comprehensive guide to the current state of consciousness studies. It starts with the "hard problem" of the philosophical relation between mind and matter, explains the historical origins of this problem, and traces scientific attempts to explain consciousness in terms of neural mechanisms, cerebral computation and quantum mechanics. Along the way, readers are introduced to zombies and Chinese Rooms, hosts in machines and Schrodinger's cat.