The Problem of Consciousness

Pause for the moment and ask yourself this question: are you conscious? You probably believe that you are. But what exactly does that mean? The fact that I am conscious seems to me the most self evident thing. Yet it is one of the most difficult things to pin down and describe. Perhaps the best way to describe consciousness is what it is like to have a view-from-within. Consciousness is the way it feels to experience. If we think about a computer that has been programmed to play chess we imagine a machine that can make very complicated decisions related to playing chess, but that it does so in a vacuum of experience. When I play chess my decisions are accompanied by an experience that there is something it is like to play chess. A computer may recognize that it is playing chess, but it has no knowledge of what it is like to be playing chess.

It is important to spend some time thinking about this because if consciousness is what it means to have an inner point of view, an inner experience, then we are left with the problem that our world seems to consist of two very different types of 'stuff'. First there is the external material world which gives rise to my inner experiences, and then there are those experiences themselves. The problem is that these inner experiences are subjective, un-sharable, and seem utterly different in their nature to the physical world from which they seem to derive. We seem to inhabit a reality in which there are two entirely different kinds of 'things', with no obvious way to bring the two together. How does the one interact with the other? How do the physical processes in my brain, the firing of millions of tiny brain cells, give rise to my personal, subjective, inner point-of-view?

Let us suppose that right now you are drinking a fresh cup of coffee, and you find your nose filled with that unmistakable smell of fresh ground coffee beans brewed with hot water. From an observer's point of view the smell is caused by chemicals entering your nose and reacting with receptors in the olfactory nerve, leading to the cascade of neuronal impulses and firings in your cerebral cortex. But from your point of view the experience has nothing to do with neuronal firing and in its quality seems utterly unrelated to the processes going on in the brain that we attribute to causing the experience of smelling coffee. For you it is like... well, what is it like? This concept of what something is like is what philosophers call qualia (pronounced qua-lay).

So the problem of consciousness starts with one of the oldest questions of philosophy: What is the world made of? It seems, initially, as though there must be two types of 'stuff' in the world: physical and mental. If you adopt this view then thought history you would have been in good company, and in fact would continue to be in good company today amongst almost all of the major religions of the world (which at their core require a belief in an immortal spirit or soul - Buddhism stands alone in rejecting the idea of a persistent inner self).

This idea that there are two elements to reality is called dualism, and the most famous example of dualism comes from the 17th century French philosopher René Descartes. Descartes postulated that body and mind interacted through the pineal gland (located in the centre of the brain). But this only puts off the problem of how the one interacts with the other. What is so special about the pineal gland? In a more modern incarnation of dualism Popper and Eccles propose that there is a "self-conscious mind" that is an independent entity that is "actively engaged in reading out from the multitude of active centres at the highest level of brain activity, namely the liaison areas of dominance cerebral hemisphere". But as with Descartes' theory, or indeed any form of dualism, the sticking point is the same: What is the nature of interaction that these "liaison areas"? If thoughts can affect brain cells than either they work by magic or they must be using some kind of energy or matter, in which case they are also physical stuff and not purely mental.

Dualism does not work. Almost all contemporary philosophers and scientists agree on this. After over 2,000 years of trying, no one has been able to provide a convincing explanation for how reality could be constructed from two separate substances. If we are going to understand who we are, and the nature of the reality that we inhabit, our only option is to deny either the physical or the mental. To do this is to adopt a monist stance.

There are two types of monism depending on which type of substance one makes fundamental. If you take matter to be fundamental, you are a materialist. Matter and energy are all that exist and subjective experience must be attributed to the interactions taking place in the physical brain. If you take mind to be fundamental, you are an idealist. All there is to the world are the ideas we have of it, but you will need to explain how and why there appears to be a physical world consistent between observers.

You may already have an idea which point of view you feel more comfortable with, but it is probably best to keep an open mind for the moment, because we shall be looking at the evidence for each in the coming chapters.