What is it we all have, yet nobody knows what it is?

“Judge someone by the questions they ask, not by the answers they give...”

We know that we are made up of cells - many billions of cells - living together in a harmonious way and forming our body. Each cell is a living entity in its own right. Our cells communicate with each other continuously. How is it, then, that this community of cells can give rise to consciousness and our sense of ‘self’? Is consciousness simply a property of our very complicated brains? Does it switch on at some stage during our development? Or is it more like a dimmer switch that can be set to different levels? And how can this assemblage of cells allow us to feel joy, or pain?

We experience the world through our consciousness. We are aware that our level of consciousness changes - sometimes we are very alert, and at other times drowsy and drifting towards sleep. We assume that other people are conscious, just like we are. When we think about other animals, we are quite willing to grant consciousness say to our golden retriever, but would perhaps hesitate to imagine that an ant, or a tree, is conscious.

How do we know if someone else is conscious? Can we look inside them and actually see what they are thinking or feeling? Even with the best imaging equipment, we can only detect brain activity that is correlated with thinking, for example changes in blood flow in different parts of the brain, and not the thoughts themselves. Consciousness is a very private thing, inaccessible to others, and we cannot know directly whether an ant, or a tree, or a bacterium, is conscious. It’s only through language that we can confirm that someone else experiences the world in the way we do.

Although we have no direct access to someone else’s consciousness, at least for now, it is still necessary for nurses, midwives, surgeons, and doctors to assess their level of consciousness in some repeatable way. So for example, after injury or in relation to an operation, a patient’s apparent level of consciousness is monitored very carefully using a protocol such as the Glasgow Coma Scale. This evaluates the patient’s ability to respond to stimuli either by movements or verbally.

Can we define what we mean by consciousness? Here are some examples of definitions:

"A comprehensive state of awareness of the mind of stimuli from the outside world, and of feelings, emotions, and thoughts from within the individual." Chambers Science and Technology Dictionary

"Consciousness is a metaperception, the vindication of perception, the perception of perception." W. Pankow

"The outside world going through the inside framework of the brain." J.M.R. Delgado

"A vital part of living that defies definition." W.R. Russell

There have been many attempts to define consciousness, and although each one captures part of the essence of this phenomenon, there is as yet no single definition that is satisfactory. However, we know intuitively what someone means by the word ‘consciousness’, so we work with that for now.

Scientists tended to avoid serious discussion about consciousness until quite recently. This is probably because four hundred years ago Rene Descartes subdivided the world into two qualitatively different realms - the material realm and the mental realm. Descartes suggested that only the material realm was suitable for scientific study. Phenomena such as consciousness belonged to the mental realm, and were therefore inaccessible to science.

In the mid-1990s, several high-profile scientists began debating the origins and mechanisms of consciousness. It had become clear from quantum theory and biological studies that consciousness was an inescapable part of our scientific explanations of the universe, and therefore must be studied. Subsequently a great deal has been written and said about consciousness, and I believe it is fair to say that although progress has been made, it is still shrouded in mystery.

Rather than presenting a long review of progress in consciousness studies, here are some of the questions that have captivated people’s attention and about which you may have your own thoughts:

Here is a koan (Taoist illustrative story): two novices were sitting on a hillside, looking at a tree. “Isn’t it wonderful how the leaves move!” said one. The other replied “it is not the leaves that are moving, but the wind!” The two novices debated this for a while but could not decide who was right. Then their mentor happened to come by, and they asked for his help in deciding between the two interpretations. “Neither of you is right,” said their mentor, “it is your thoughts that are moving”.

What is mind? - No matter
What is matter? - Never mind...