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What is consciousness?

An Introduction

There is something that it is like to be conscious. It is a unique experience and cannot be described easily. It is not possible to characterize it in any physical terms; in fact to describe consciousness one requires adjectives which are only related to being conscious. We constantly seek words to sum it up but end up in a circular state. It seems to be in a different category completely from the rest of our world or even our universe. And this is perhaps the greatest difficulty in the philosophy of consciousness: how can we work out how something physical such as our brains could produce such a phenomenon?

Abstract and artistic view of brainConsciousness is not the same as being awake, because we can have conscious thoughts when we are dreaming. Also, it does not correlate with my medical training about consciousness, in which we measure levels of consciousness in sick patients.

In many ways we are unconscious of being conscious. We are a bit like fish swimming in water; it is their entire world and yet it is possible to imagine them not realizing that water even exists. It is so normal to be conscious that we tend to ignore the fact that it is an amazing and wonderful thing. We take it for granted until we are asked to describe it.

Private access

One of the defining features of conscious states is that they are a private world. Only you are privileged to know the thoughts that you have – no one else can have them. It is subjective and no matter how skilled I am at describing my thoughts to you, I cannot really convey them properly. We always refer to examples of our own thoughts in order to try to understand the thoughts of others.

In fact there is an interesting philosophical argument that you might like to ponder and it goes like this:

  1. Mental states can only be privately accessed.
  2. No physical state can be privately accessed.
  3. Therefore mental states are not physical states.

Actually that might seem obvious, but many philosophers would argue that in fact mental states are just physical and that it is an illusion to think otherwise. You might be asking yourself why they would say this. It is because many people have a world view that says there is nothing more than the physical in the universe, just matter, energy and time. You might expect philosophers to have a more rigorous means of deciding this, but a priori world views do seem to heavily influence the debate on the mind.


Consciousness involves a sense of personhood. I know who I am as an individual person. Now this might take time to develop in children but there is no doubt that as persons we are uniquely aware of our individuality. There is a continuity in my life; I am the same person that I was 10 years ago. I might have changed but I am the same unique individual. We struggle to imagine how any physical object or machine, however complex, could have this sense of personhood. It is not just that there is the continuity between myself now and as I was years ago, it is much more than that. Having a first person knowledge of “me” is something no one else can have and which has a phenomenal quality that almost defies description. And of course we know this about others too; our friends and family are persons in their own right who are individuals that we instinctively feel are not physical but entirely and uniquely ‘them’. When I speak with or write to someone, I do not believe I am addressing a physical object. I am addressing a person.

Artificial intelligence (AI) enthusiasts will maintain that some machines behave like persons and therefore cannot be said to be any different. But the difference is obvious; machines are programmed by us to appear as if they are persons when they are clearly not. When my computer speaks to me or the Sat Nav directs me to turn right at the next roundabout, I may like to fantasise about the machine being an actual person but I would of course be entirely wrong. AI may do wonderful things but the most advanced forms are merely copies of what we do, and not individuals in their own right. John Searle in a classic paper has dismissed the possibility of computers becoming conscious.[1]


Consciousness involves sensations. For example, the way in which I experience the colour blue. There is a ‘blueness’ about blue that it not merely registering certain wave lengths of light (as a machine might do). There is the smell of something such as the coffee I made this morning. There is the sound of the wind I am hearing around this building I am in. There at times may be an itch or a pain somewhere in my body. Such experiences of sensations are known as qualia in philosophical language.

If we go back to the experience I have of seeing the colour blue, for example; there is something very deep going on. I do not merely register a wavelength, I have a unique experience. Once again it is helpful to contrast this with what happens with a robot which registers blue (by analysing wavelengths of light). The robot might even speak and say “wow, that is a wonderful blue!”. But the robot will not have had any experience of blue at all, merely registering a wave length and converting the data into speech via pre-programmed zero and ones.

We have to ask ourselves therefore whether the experience, the qualia, of seeing a colour is a non-material event. Materialism, (which has nothing to do with shopping), is the view that all that there is in the universe is matter and energy. What we sense strongly and may even conclude, is that conscious experiences such as qualia are non-material events. This is known as “The Hard Problem” of philosophy of mind, a phrase from the philosopher David Chalmers.[2]

There is a famous thought experiment by the philosopher Frank Jackson known as ‘Mary’s room’.[3] Mary is a neuro-scientist who knows absolutely everything about vision. In fact she knows every physical fact about the process down to the sub-atomic level. Yet, Mary has been brought up and stayed in a room that is entirely black and white with no colour, all her life. She has never seen colour. She of course knows all that there is about the process of colour vision but never experienced it. She is then brought out of her room and she experiences colour in the world around her. This is a completely new experience. She has added to her knowledge of vision the actual phenomenal experience of colour vision. This is a new form of knowledge. We can state the situation as follows:

  1. Mary does not know all the facts.
  2. The physical facts do not exhaust all the facts.
  3. Materialism is therefore false.

Materialism is the belief that the only things in the universe are purely physical ones. It seems, from Mary’s experience, that such a belief is false because the conscious experience of colour vision cannot be reduced to something physical. Philosophers do argue over this endlessly but many would indeed agree with this assessment.

Correlation of person and brain

The thought experiment ‘Mary’s Room’ brings up the issue of brain activity and consciousness. For every thought there is some activity of the brain associated or correlated with it. We can see this with MRI scans. The big question is this: is the neuronal activity all there is or is it merely correlated with consciousness?

When my car is driven from A to B it is taking part in the journey. But that is not all there is; it is I who am driving it. What if anything drives the brain?


Consciousness of course also involves emotions such as sadness, fear, anger, hopes and love. These are deeply personal and real. In fact like all of consciousness, it is very difficult to categorize such emotions with any form of physical order or terminology.

Emotions are ‘about’ something and they have content. This ‘aboutness’ is known as intentionality among philosophers. Can these thoughts be merely physical? How can a physical object be about something? When we look at physical things in the universe we know that they exist and they interact with other physical things. They may have complex relationships - think of the weather systems for instance, or the way molecules interact in the human body. However we cannot say that any of these things are ‘about’ anything other than that they exist in such relationships. An emotion, in contrast has aboutness – such as the grief after losing a loved one or the anger towards that bully at school or the love for that person you want to marry.

Emotions are also surely distinct from physical events in that they have clear and non-physical attributes when we feel them. This is like the discussion we had about qualia; there is something it is like to have an emotion such as joy. Joy is uniquely personal and cannot be reduced to something physical.


Beliefs are an essential part of our conscious lives and also have this sense of aboutness. If I believe that Tolstoy is a better writer than Dickens, then I am more likely to read his novels. This belief may perhaps be justified by me giving examples of both writers and analysing them. But in the end my belief that Tolstoy is better at writing is a subjective thing that is not reducible to facts or indeed anything physical. A belief stands on its own somehow. How could it be reducible to neurones signalling one another – even if such neuronal activity is correlated strongly with having the belief? Can a physical event or events in my brain can have beliefs?

We also have the question of whether a belief can affect the brain in order to do something (such as bring my umbrella). If a belief is not physical then how can it affect something physical such as the brain? This is ‘the’ crunch question in philosophy of mind; can a non physical thing such as a conscious belief have any effect on a physical object such as the brain?


As individuals we have a strong sense that we have choice and can freely decide to do different things. As such we believe, rightly or not, that we have a degree of autonomy. We have a sense that we can choose to buy a certain article or to go up to someone to speak to them, for example. We award people who choose to do brave things in war, and give them medals, because we feel they could have chosen to do otherwise. We punish people who do bad things because we believe they could have chosen another course.

The big question is whether a purely physical object such as the brain, however complex, could have free-will. The reason this is controversial is that any purely physical system is subject to the laws of physics and cannot do otherwise than what it does. External physical conditions may affect the outcome, but there is no freedom that we can see within such a purely physical state. And quantum randomness at the atomic level does not help to explain free-will, because being random means a lack of any autonomy or real choice.

If we really do have autonomy to choose, then this is a massive argument for the non-material nature of the mind.


While not strictly part of philosophy of mind, moral and ethical thoughts are central to our very nature. All of us, apart from very few exceptions, will argue strenuously for our moral values. These are firmly held positions on such things as fairness, equality, benevolence, justice and human rights (for example). We might differ on the details but we will agree on the basic moral positions. Most of us would agree that it is simply wrong to cheat in exams or to commit murder. We take such views for granted, and we generally hold them as absolutes. They are part of our consciousness but these are views about the world and others which we feel are outside of us. They do not depend on our particular state of mind; murder is wrong – whether you or I think so or not.

Where do such values come from? The materialist will attempt to invoke such things as social Darwinism (it is good for the extended kin and thus gene survival). By doing so they demote such morality to mere survival tactics, rather than to anything universal.

And so if you think murder is wrong per se, you are already showing a strong leaning towards something immaterial and universal. Where do such universal values come from?

Monism and dualism

It is worth defining some philosophical words that repeatedly crop up.

Monism is the view that the mind is entirely one substance. ‘Substance’ in these discussions does not refer to only physical things but can refer to non physical things (such as the possible non-physical mind).

Dualism is the view that the mind is distinct from the brain or body and is not reducible to certain forms of neuronal brain activity. It tends to come in two forms: Property dualism holds that though distinct from the brain, consciousness is entirely a product of physical brain activity. The term used is often ‘supervenience’. The mind is supervenient on the brain, and is in this sense immaterial, but is entirely a product of the physical neurons and cannot exist independent of them.

Substance dualism, which is the view that was held by the philosopher Descartes,[4] says that the mind is distinct and is a different ‘substance’ from the brain. It is a non-physical substance. It interacts with the brain and is closely linked to the brain but can exist without brain activity. The interactions it has with the brain are both ways; the brain can act on the mind and the mind on the brain.

Substance dualism holds that there is in fact something we might call a soul in each of us. The soul is the actual person and is autonomous in that the soul has free-will and is not dependent on the physical brain for decisions.

As we get deeper into the study of consciousness we realize fairly quickly that it is something to wonder at and appreciate. You may wish to read the article ‘Mind the Gap’ which goes into more detail about the current philosophical positions about the mind.



[1] Searle, John. 1983. Can computers Think? From Minds, Brains and Science, pp. 28-41. Harvard University Press.

[2] Chalmers, David. Consciousness and its Place in Nature. From Blackwell Guide to the Philosophy of Mind. Blackwell. 2002

[3] Jackson, Frank. ‘Epiphenomenal Qualia’. Philosophical Quaterly. (1982) 32:127-136

[4] Descartes, René. 1641. Meditations on First Philosophy. Cambridge University Press. 1985

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Antony Latham, 20/07/2017