Consciousness: An Evolutionary Approach

Tony Wilson BRLSI Member

4 July 2006


What is the relationship between the mind, which is abstract, and the brain, which is real? Evolution yields an embarrassingly simple answer, which is that the mind is real. Evolution also says that noticing that you are aware of yourself, and wondering what this means, is merely an introspective puzzle, like infinity. And like infinity it doesn’t mean anything at all. Why should it?

What is consciousness?

‘What is the relation between the mind which is abstract and the brain which is real?’ It’s an eternal question. Is my sense of myself, my consciousness, just a physical event in my head made up of nerves cells, circuits and chemicals? This seems impossible; how can our fleeting thoughts have physical form? So is it some abstract but undiscovered thing outside of our physical bodies, like a soul or spirit? This too seems impossible.

The answer I will propose this evening is that consciousness is a real physical phenomenon, taking place in the brain: a series of chemical or electrical events, which, if we had the instruments, we could observe and measure. I suggest that the philosopher’s dilemma about consciousness is nothing more than the sense that you are aware that you are aware of yourself. Like the contemplation of infinity, the consciousness question is nothing more than an insoluble introspective puzzle, a meaningless conundrum.

The approach I suggest could be called ‘Reductio ad Bacterium’. It is to start with a scientific view of the origin of life and to test whether self-awareness could be an attribute without which life would be impossible. Life, I believe, would be impossible without motivation. I will be exploring whether the same thing goes for self-awareness. I will suggest that the evolutionary explanation of consciousness turns out to be embarrassingly simple. It goes to the very heart of classical philosophy and at the cutting edge, proposes a much simpler solution. This is a solution, which is cold and clinical. It is important for us philosophers because it threatens to destroy many cherished beliefs; especially those about the importance of mankind.

I shall assume that you accept Darwin’s explanation of how life evolves by the process of natural selection. Furthermore I do not propose to divert myself into any of the fascinating evolutionary debates of recent years such as gene thinking, negative entropy, or self-organisation (emergence), because they do not significantly affect what I have to say. My talk will deal mainly in metaphors. I will be inferring what must happen in the brain to create the sense of consciousness, but when it comes to the cutting edge I will not be backing up what I say with scientific facts. That is for two reasons; first I am not a biologist, and second, the cutting edge neurobiological facts about consciousness have not been established.

States of consciousness

Firstly, I need to distinguish five different levels of consciousness:

To be conscious the creature has to be alive.
If it is alive but asleep it is not conscious.
If it is awake but not contemplating its self it is simply conscious.
If it is awake and referring to its self for functional reasons it is self-conscious.
If it becomes aware that it is self-conscious, and wonders about that, it is doing a Descartes. It is contemplating the meaning of consciousness. And that of course is what we are doing tonight. I call this fifth level ‘philosophers consciousness’.
When contemplating yourself in the mirror you are in this fifth state of consciousness. This is more than referring to yourself for the purpose of putting on a hat; you are directly confronting yourself; you can see that you are aware of yourself – confronting your own sense of self. But how often have you done that today? Not very often. And where did it get you? Not very far.

People used to think that of all the creatures on earth homo sapiens is the only one capable of self-awareness. But there is no scientific basis for this belief and dog owners might suggest that you are almost certainly wrong.

The essence of life, or Reductio ad Bacterium

If you set out to create a living organism in the laboratory you would have to list the essential features of life, and because the organism you create must be able to evolve you would start at the very simplest level: Bacteria.

Here is my list of the essential features you must give a laboratory bacterium before you can claim that you have created life:

Your organism must have a structure: a skin or boundary, a body and a nervous system.
It must be able to metabolise: meaning to eat, protect its self and reproduce. Furthermore if the method of reproduction you have chosen is sexual you’ll have to make two bacteria.
It must be motivated to metabolise. I call this the prime motivator.
I call these three essential features: STRUCTURE, METABOLISM & MOTIVATION.


Next your newly created life form, a laboratory bacterium, must be put into a suitable environment, probably a nutritious liquid to get on with its life. If your experiment has succeeded it will seek to survive and prosper. It will feed, avoid danger and reproduce. Eureka! You have created life. You can look at your bacterium through a microscope, see it retreat from danger and advance towards opportunity; watch it messing about as it eats, shelters or reproduces according to its motivations. Watch it try this... fail... try that... succeed... remember... try again. I call this purposeful messing about NAVIGATION. And the reason it can navigate is because you have endowed it with the necessary structure, metabolism and motivation to do so. I suggest that every living thing (from fungus, plant and animal) must be able to navigate in order to survive. How else could it exploit opportunity? So I define the word ‘navigation’ broadly here, and will say more about it later; it is central to my theme.

Self awareness

If I’m not aware of myself there’s a break in the circuit of life; no message can get through. I can’t be motivated. If I am totally unaware of myself I cannot function (other than by reflex action); I cannot direct my movements, so I cannot navigate.

Even in a bacterium the prime motivator, life-feature (no 3) must entail at least a rudimentary spark of what in higher order creatures will evolve into self-awareness. As with all reflex actions like the beating of my heart, a bacterium responding by reflex action to an external stimulus does not need to be self-aware. But as soon as life evolves the ability to choose how to respond by comparing the importance of different external and internal inputs, then higher order cognitive processes must entail what is a primitive version of self-awareness. Current research by professor Dennis Bray, working on E. coli at Cambridge University, and elsewhere suggests that even bacteria must be endowed with this ability.

If your bacterium has no sense of its self - of where its body begins and ends -if it cannot recognise the difference between its self and the outside world, then the motivation to metabolise (eat, shelter from danger and reproduce) makes no sense. Without an idea of self you have not given your bacterium anything to prevent it from eating its own tail.

What I’m saying is that self-awareness is a pre-requisite of motivation. You can’t motivate yourself if you have no awareness of yourself. This is the cutting edge of the question of consciousness.

So to repeat; every life form must be self-aware at least to some rudimentary degree – even fungi and plants. Otherwise how can they exploit opportunity and avoid danger. Higher up the evolutionary ladder we get animals with brains. And in them this rudimentary spark has developed into full self-awareness.

What must happen in the brain

Enormous neuro-scientific, cognitive research is going on into how the brain actually works. It’s obvious that even spiders’ brains are immensely complicated and yet we simply don’t know how they work. So we have to make do with theories, and my talk this evening is shamelessly riddled with theories, similes and metaphors; that after all is what characterises philosophy in comparison with science. It is a method of thinking to develop explanations about life for science to verify or reject.

In fact of course we do already know a lot about the human brain, so it is not difficult to infer with some confidence what must go on in here even if we don’t know how it’s done. After all it seems clear that the brain receives inputs, processes them and directs our actions.

It’s also more or less certain that somewhere in here lies the answer to the age-old question of consciousness.

Several things have I believe been put beyond dispute by science.

The human brain has evolved from the earliest forms of life. There is no break or magic link in this evolutionary chain. There’s nothing that sets humans apart from all other life forms. We are not categorically different in the way that water is different from sunlight.
When it is conscious (awake) the human brain receives continual inputs from our five primary senses. Sight, sound, taste, touch and smell.
It also receives pleasure/pain reports such as hunger, pain, lust, etc from its internal organs.
The brain remembers much of what has happened.
When the brain is asleep these inputs are turned down but not shut off.
The brain decides what to do by combining its prime motivator, its sight, sound, etc. inputs and its memory. We refer to this as thinking. By this definition all animals think.
The brain instructs the nervous system to act accordingly.
There is a feedback process here that I see as a navigation cycle because it’s like navigating a ship. You set out for your destination, review progress, alter course accordingly, enter everything in the log, review progress again, alter course accordingly, repeat continually till you get there. Engineers refer to this as a cybernetic control loop, but their definitions, having variable elements, are usually less strict, less universal, than mine. I’ll return to this point later.






Navigating an 18th century tea clipper

I’m talking about ‘what goes on in the brain’ so that we can trace the evolutionary basis of consciousness. But first I want to show that these navigation cycles apply to all sorts of human endeavour. [5] illustrates the mnavigation cycle for an 18th century tea clipper. Its purpose is to bring a cargo of tea from Calcutta to London by 1 May. The navigation cycle iterates continually - reviewing inputs, deciding course direction and speed and





These same principles apply to programming a robot, like for example driving the computer-controlled cars that occasionally race across the Mojave Desert in America. They also apply to running a business or governing a country. And the concept of navigation cycles will be central to what I have to say about the evolution of consciousness.

The evolutionary perspective

Next, I need to set the scene by referring to the uninterrupted, gradual development of the brain from the very origin of life - from the living organism that you have created in your laboratory - to the human brain.

I have taken the following information from Ernst Mayer’s, What Evolution Is (2001):

We now know from geology and astronomy that the earth was formed about 4.6 billion years ago.

The first true life forms were the bacteria. It is widely agreed that the fossil record tells us that the first bacteria can be traced back to 3.8 billion years ago. Bacteria still make up about half of the biomass of life on earth today. The first bacteria were tiny, had a primitive nucleus, only reproduced by splitting (not sexually). And they muddled about feeding, self-protecting and reproducing at random. Next, Mayer says, after one billion years (an unimaginable length of time) of exclusively bacterial life on earth the most important and dramatic event in the history of life took place – the origin of the eucaryotes. All life forms as we know them, apart from bacteria, have evolved from the eucaryotes.

What happened apparently was that a chimera, like the mythical centaur; half man, half horse, was created through symbiosis, or living together, of two different types of bacterium. This is inferred from the genetic makeup of the eucaryotes.

The eucaryotes then quickly acquired a membrane-bounded nucleus in their cells (with chromosomes), and evolved sophisticated nervous systems. They also developed sexual reproduction.

And from there the rest of life has evolved.

Pigeonholes and consciousness

To return to the question of what consciousness actually is: somehow the primitive brain must make use of random incoming data (I mean pigeonholing it in much the same way that a post office sorts incoming mail for distribution). Even the very most primitive living organisms, bacteria for example, must be able to do this.

It follows that the primitive bacterium you have created in the laboratory must have a minimum of 3 pigeonholes. One each for deciding about the three metabolism jobs that I have already described: to eat (absorb energy), protect its self and reproduce. And I’m also saying that each one must in effect be a trinity principle navigation cycle, because it receives inputs, decides and remembers for next time.

[6] shows a highly simplified and stylised scheme of what I mean.












These are not reflex actions they require choices; consciously made. Again the word consciously here is at the cutting edge of this whole enquiry. Without this rudimentary sense of self the organism cannot function. Natural selection would wipe it out because motivation would be denied.

Nicholas Humphrey says in Seeing Red: a study in consciousness (2005):

So for primitive creatures at an early stage of evolution, the surfaces of their bodies separated self from environment. For them, interactions with the environment involved nothing more than automatic, reflex responses. Factor in time and increasing complexity and the creatures did better (survived longer, bred more) by developing systems able to keep track of these reactions. They could, for instance ascertain which responses had better or worse outcomes, and learn to avoid the latter. Over time, such tracking systems became divorced from stimulus response systems, allowing them to do other useful things such as rehearsing potential responses without having to act them out. The tracking system became more ‘privatised’ and the ‘self’ internalised.

Neuroscience will, I hope, correct my crude picture of a cartoon-like brain crammed full of little navigation cycling pigeonholes. Hopefully neuroscientists will soon arrive at a consensus about the workings of the brain. When they do I expect that the principle of a hierarchy of these metaphorical pigeonholes with navigation cycling facilities will be substantially confirmed. One solution might be a central facility, available to all pigeonholes; both hardwired and temporary. A facility where instant processing is done, and memory created, with subsidiary brain centres feeding into and taking from this facility.

I am of course talking in metaphors here, and this is what I meant when I said earlier that the philosophical method relies much of the time on metaphor. (Oxford Dictionary: ‘a thing considered as representative of some other thing’) Plato’s cave is a metaphor, so are Nietzsche’s superman, Marx’s dialectic, Kant’s Copernican revolution. Hobbes, Sartre, Rawls... They all used them extensively.


Understanding is thus the process of deriving useful conclusions from the chaotic rapid-fire jumble of real-time inputs from the primary senses. Thinking is very much the same thing; it is the subjective, self conscious aspect of understanding or the planning aspect of navigation.

When we learn a new skill; say learning to play the piano, to type or drive a car, new pigeonholes are set up. Such pigeonholes are temporary at first; they will wither away without regular maintenance. We are born with many of these blocks or pigeonholes, others we develop as we build life experiences.

Intuition is what happens when a navigating animal jumps to a conclusion before the full set of sight, sound, etc. updates is available. When speed is important, as for an opening batsman facing a fast bowler, the organism seldom waits till all the sensory inputs are analysed.


In sleep these higher-level blocks or pigeonholes are shut down, but not off, for tidying and maintenance, at which point we lose consciousness. Our life slows when the sun goes down and night is a good time for metabolic rest and repair. Natural selection has not designed our pigeonholes and their interconnections to tidy and repair themselves as they proceed; they become cluttered and messy during the working day, some need enlarging, others reducing and so on. So during the night our bodies take the opportunity for a 90% mental shut-down so that this work, which would otherwise interfere with our life functions, can be carried out more efficiently. It’s like waiting for the office workers to go home before the cleaning ladies and maintenance staff come in. Or to put it another way a sleeping brain is like a defragging computer.

The movie-in-the-brain

I shall end this description of interconnected navigation cycling pigeonholes by quoting Antonio R Damasio. In an article published in the Scientific American, August 2002, he refers to ‘The movie-in-the-brain’. This is what he said about ‘the biological foundation for the sense of self":

Simply put my hypothesis suggests that the brain uses structures designed to map both the organism and external objects to create a fresh, second order representation. This representation indicates that the organism, as mapped in the brain, is involved in interacting with an object, also mapped in the brain. This second order representation is no abstraction; it occurs in neural structures such as the thalamus and the cingulate cortices... Such newly minted knowledge adds important information to the evolving mental process. Specifically, it presents (sic) within the mental process the information that the organism is the owner of the mental process. It volunteers an answer to a question never posed: To whom is this happening? The sense of a self in the act of knowing is thus created, and that forms the basis for the first person perspective that characterises the conscious mind.

Damasio then goes on to say that a self aware organism has an incentive to heed the alarm signals provided by the movie-in-the-brain. With a nod towards Darwin, he says that this gives a clear survival advantage over organisms that are not self aware.

Self awareness and introspection

Having used ‘reductio ad bacterium’ to speculate about self awareness in the human brain I’ll now come to consciousness in the strictly philosophical sense. This, as I mentioned earlier, is the fifth level of consciousness. Philosophers consciousness is the thoughtful awareness of self-consciousness. Like gazing in the mirror it is essentially an introspective process.

Consciousness in this philosophical sense occurs at a higher level than mere self-consciousness. Self consciousness is a permanent and basic life feature, essential for navigation. But the philosophical puzzle; that one is conscious of ones own self consciousness, occurs when the whole process is turned in on its self.

There is nothing to stop us, and almost certainly other highly evolved animals, from observing our own self awareness. We have evolved the necessary mental equipment to do so in the form of:

a. navigation cycling pigeonholes,

b. the ability to sort and compare their contents,

c. the ability to derive understanding and meaning from them, and

d. the ability to think about this meaning.

The trap

The clown’s game, ‘Pete & Repeat’ illustrates the meaninglessness of infinity: Pete and Repeat sat on a bench. Pete fell off, who was left? Repeat. Pete and Repeat sat on a bench. Pete fell off, who was left? Repeat...

What does ‘for ever’ really mean? Nothing can go on ‘for ever’, and yet infinity says it does. Like infinity, the self-aware sense of the workings of our brains is impossible to comprehend. You give up thinking about it after the third repeat. You can’t comprehend infinity, you never will and it doesn’t actually matter. The same applies to consciousness: it is the knowledge that you are conscious that you are conscious, and that you are conscious that you are conscious that you are conscious, repeating into infinity. It follows that using a subjective approach to achieve either a scientific or a philosophical explanation of philosopher’s consciousness is to attempt the impossible. It merely leads into the jaws of what I call the introspection trap


The question was: ‘What is the relation between the mind which is abstract and the brain which is real?’

I suggest that the mind is not abstract; it is real and it occurs in the brain in the form of nerve cell connection events. The mind is a physical thing, and self-awareness is a basic biological necessity, which occurs in the bodies of all animals. It is, I believe, entirely possible that one day neurobiologists will be able to observe and measure it. Once that is established it becomes obvious that one can’t prevent a higher order animal from being aware that it is self-aware.

My definition of ‘philosopher’s consciousness’ is that it is this self-aware sense of contemplating the meaning of consciousness (in other words, of contemplating the workings of our navigation-cycling pigeonholes). Without these no animal can navigate to survive and reproduce. Self-awareness permeates and makes sense of the whole system.

This definition sidesteps the introspection trap which entangles classical philosophy, and being very much easier to express in plain language it claims precedence over them in the test known as Ockham’s razor which says that entities are not to be multiplied beyond necessity, or that it is pointless to do with more things that which can be done with fewer.

If you set out to create life you must give it self-awareness otherwise it cannot function; it might even eat its own tail. When you endow life with self-awareness you cannot prevent more highly evolved brains from being aware that they are self-aware. And you cannot prevent them from falling into the trap of puzzling about what that means.

As I said at the beginning, the evolutionary explanation of consciousness turns out to be embarrassingly simple. It goes to the very heart of classical philosophy and at the cutting edge, proposes a much simpler solution. This is a solution, which is cold and clinical. It is important for us philosophers because it threatens to destroy many cherished beliefs, especially those about the importance of mankind.

Tony Wilson