You Are Not Your Brain

[Back to Human Identity]


Over the past few years, I have read many articles, and participated in many discussions, which touched on what it means to be human, what it takes to be self-aware, and the nature of consciousness. Whatever the different perspectives and positions being argued, on each occasion, there was one key assumption: the key thing which makes me ‘me’ is entirely tied up with the lump of meat we call the brain.

Sometimes the discussion is not about the brain, but the mind – it makes no difference: the ‘mind’ being discussed was a thing which always depended on what happens in the brain.

But I think this way of understanding humanity and consciousness is deeply mistaken: whatever you are, you are not your brain. At least, you are not just your brain. At the most fundamental level, I believe, you are your body. Your body includes your brain, of course, but it also includes heart, lungs, kidneys, arms, legs and all the rest. Forgetting this basic truth leads us to misunderstand who we are and what we have.

Looking Back

The idea that the real, essential ‘you’ is your mind goes back a long way: we find it in the classical Greek writings, which describe human beings as an intelligence (/mind/spirit) trapped in a body. It is the understanding which underpins any belief in reincarnation: you can be set free from your body, and go on to live in another body.

In contrast to the Greek understanding that a person is a spirit trapped in a body, the classical Hebrew writings describe human beings as an animated body. In Genesis, we read that God formed a man from the dust of the earth and breathed into his nostrils the breath of life and the man became a living being (Genesis 2:7). it’s quite clear: God formed the man, the physical body, so you had a man but no life, and no mind. Then God gave this man life, and the man started to live – to breathe, to move, to think. The man had a body before he had a mind.

This is why we treat the dead human body with reverence: this once was a human being. A snake can shed its skin, or a crab can shed its shell, and simply discard the old covering; but for us, even once the life has departed, the body remains precious – what we do with it matters. It is not just a prison cell which is no longer required.

Looking Around

In everyday life, we function within the Hebrew tradition, rather than the Greek one – on this point, at least. When I miss a meal, then I am hungry. It’s not that my mind is observing that my body is hungry: I am hungry. When my leg breaks, I am hurt. If my leg is amputated, I have a part missing.

If my body does not get enough to drink, then I am thirsty. If we meet when you are hungry, thirsty and tired, I could try to tell you that none of this matters: you are really your spirit (or your mind, or however you care to describe it) – you can still think and reason perfectly well, so the ‘real you’ is not affected by these physical concerns. I could try it, but I won’t, because I am pretty sure I can imagine what the response would be.

One of the first things a baby discovers is the difference between me and not-me: I suck my finger and I can feel both the sucking in my mouth and the being-sucked in the finger; when I suck your finger, I can only feel the sucking in my mouth. My finger is me, your finger is not-me. And, after a while, I discover I can control bits of me, so I can place my finger in my mouth, then crawl, then walk, discovering increasing levels of control of myself. I feel hungry, then feed, then feel content: my feelings lead to my actions, controlling my body, and those actions produce different feelings. And, in all this learning, and this increasing ability to control, the boundary I discover between me and not-me is simply and consistently my body.

Of course, in some ways, my body is just a machine, which modern medicine can often fix when it goes wrong. But to recognize that my body is a machine is not to say that my body is only a machine: that would be the old fallacy of ontological reductionism (or ‘nothing buttery’, as it is sometimes called). ‘Marriage is a civil institution’: true; ‘marriage is nothing but a civil institution’: false.

Because the body is a machine, we have learned to replace parts when they go wrong, and organ transplants is now a common activity. And we have an interesting relationship with the transplanted organ: it seems like me, it functions as a part of me, but it doesn’t quite feel like it is really me. It seems to exist in a category all of its own, but not one for which I have an innate space – it is not quite me, but it’s not entirely not-me either. No wonder that some people who have transplants start to wonder who they are now.

(For more about the distinction between me and not-me, and why the body is not really - not just - a machine, see The Ghost in the Machine.  For more about the attributes of living organisms, and how they differ from machines and virtual entities, see Real Life.)

Looking Inwards

I have needs: air, water, food and physical safety being the most obvious. I have desires – again, there are some obvious examples: to survive (to see my needs met in the short term), to be safe (to be confident that my needs will be met in the medium term), and to succeed (to successfully reproduce) in the long term.

These needs and desires are built into my physical existence, hard wired into my DNA from the moment of conception. A great deal of my physical activity is directed towards gaining the things I need, and almost all my internal activity – lungs, heart, kidneys, stomach, gut and all the rest – is directed towards using the air, water and food, to enable me to achieve those desires.

And while my needs and desires may be hard wired into my DNA, much of the DNA in my body is not mine: there is a large and complex ecosystem of micro-organisms living in my gut.  My health and my emotional state both depend on these organisms - an important detail which modern science is only just catching up with.  I am not only more than my mind, I am more than my body, more than my genetics and experiences.

A fair chunk of the brain is taken up with controlling and regulating all this activity: I may not be conscious of it, or (as with the case of breathing) only partly conscious, but the brain is constantly monitoring both electrical signals through the nerves and chemical signals through the blood. The conscious, the partly-conscious and the subconscious are all deeply intertwined within my physical being.

The brain is essentially a goal-directed prediction engine.  The goals are set by the body: survive, be safe and reproduce; everything else, more or less, can be seen as a way of achieving these goals.  The brain predicts the future, then, in the light of that prediction, plans how best to achieve these goals; then it predicts the consequences of the planned actions and constantly compares experience against the predicted experience, adjusting activity as needed when the two don't match.

I don’t only care about survival and success, I also care about social and spiritual matters: friendship, status and politics; love, truth, justice and freedom; it's fairly easy to see how these 'higher' concerns translate back into the more basic ones.  In any case, I can’t care about all these things if I don’t also care about staying alive, and about having the power to shape my environment and, through it, my future.

And the practical realities of survival and success also shape the ‘higher’ concerns: much of friendship involves eating and drinking together; status and success are long-time bedfellows; much of the work for justice involves seeing that other people can survive and succeed; and so on.

For many people, a significant part of their identity is tied up in what they do, but for a pianist, a painter or a plumber, their skill lies not only in their knowledge, but also in their muscle memory, parts of which seem to reside not in the brain but in the spinal cord. Your body knows how tight that nut should be, and the correct consistency the mixture should reach before you bake it. You may not feel you have much physical expertise, but the body is never just a machine which obeys the commands of the brain - try to write your signature with the wrong hand if you are not convinced.  Gaining expertise lies as much in moving skills out of the mind as it does in moving knowledge into the mind.

And while a brain may conceivably be fed virtual information (as The Matrix imagined), a body must exist in a very particular relationship with a very specific environment: it needs a world to exist in. In short, the physical realities and necessities imposed by my body are completely entwined in my identity, and also entwined in many aspects of the matters I usually associate with my mind.

Looking Forward

Discussions of Artificial Intelligence and the future often circle around two big questions. Can an advanced computer (using, perhaps, some as-yet-undiscovered technology) ever be conscious and self-aware? And will we, one day, be able to upload our consciousness into a computer (perhaps ‘in the cloud’) so that I will be able to live forever – or, at least, until the electricity gets switched off?

My identity is primarily tied up with my body: my experience, skills, beliefs and abilities may distinguish me from other people, but I am not simply the sum of these things: somebody else could potentially come along and do everything I am capable of doing – that person may be identical to me, but that person would not be me.

In contrast, a computer has no body, and no computer – no machine – has an identity in the same way that a living creature has: if I lose my arm and you replace it, I will be grateful, and it may function as my arm, but I will always have someone else’s arm attached to my body; but replace one transistor in the computer with another, or move the software from one machine to an equivalent one, it makes no difference. Copy the program onto a million equivalent pieces of hardware, and you have a million copies of whatever you started with. Identity works differently with machines and living creatures.

You could, perhaps, one day be able to replicate the neurons in my brain with functionally equivalent software. But those neurons are triggered by messages from my skin, muscles, gut, kidneys and bladder: every part of your body sends messages to your brain.  It is also affected by the proteins and other chemicals carried in your blood from glands all over the body, which change if you feel hungry, or get angry, or do almost anything, really.  And then if your use cannabis or LSD or eat, drink or smoke many other psychoactive drugs (such as chocolate...), your brain is affected, not because your neurons are changed, but because their chemical environment has been changed.

Even if you could replicate both the neurons and their chemical environment, this 'functionally equivalent' software might be able to tell you the capital of France and how to sum the first hundred digits, but it will not be able to enjoy the taste of a good quality single malt; and even if you manage to replicate the chemical analysis performed by my palate, it will not experience the effect of the Scotch as it slides down my throat, slowly enters my bloodstream, and affects the various organs in my body. It may be able to do many things, but it will not be me.

As a living being, I have some basic needs, which are tied up with my one overriding need: to survive, to continue living. And I have some basic desires, which are tied up with my one overriding desire to reproduce, and to enable my children to survive. Success, for any living creature, means, at the most basic level, enabling your children to successfully reproduce.

In contrast, a program has no innate needs or desires, and it is not clear what these could even look like. You can program it to play chess or fold proteins, and you can program it to learn how to do these things, but you cannot program it to feel hungry, scared or lonely. A program has no self which is can seek to preserve, and it can have no children to carry on the flame of life after it has died.

Many years ago, I read the ‘Robot’ books by Isaac Asimov; it seems to me that his vision of the future of artificial intelligence has stood the test of time, and rarely been equaled. I don’t see how his ‘three laws’ could be programmed, but if it can be done, then one day these laws, or something like them, could potentially give the robotic equivalent of a sense of purpose to artificially intelligent machines: not the same as the needs and purposes which drive living creatures, but not totally disconnected from them either.

Artificially intelligent machines would have value. Apart from any purely financial consideration, and apart from considerations of the value of what it can do, once a machine starts to interact with the world, it will experience and learn unique lessons and so become unique. A human life will always be more precious, but these machines would each have value, as I see it, like a beautiful and unique work of art.


You Are Not Your Brain is a link to the original version of this blog as a PDF.

Postscript: The day after I posted this, David Robson posted an article which ties in very nicely, describing lots of connections between the brain and the body which I didn't have the space (or technical knowledge) to cover: Interoception: the hidden sense that shapes wellbeing.

And, in October 2022, Moheb Costandi published Body Am I, which seems to cover much the same ground as this post. If anyone has read it, please let me know!

In January 2023, the BBC published How gut bacteria are controlling your brain, which beautifully illustrates some of the points made above.  It points out that "the gut and the brain aren't entirely independent of one another but instead interact, with one influencing the other and vice versa. And now we know that the microorganisms within our gut make this process even more complex and remarkable."  The article includes this quote from John Cryan: "In medicine, we tend to compartmentalise the body.  So, when we talk about issues with the brain, we tend to think about the neck upwards. But we need to frame things evolutionarily. It's important to remember that the microbes were here before humans existed, so we have evolved with these 'friends with benefits'. There has never been a time when the brain existed without the signals coming from the microbes."

Understanding the brain as a prediction engine is well established; a nice description of this idea and the experimental evidence can be found in an article by Jordana Cepelewicz ('To Make Sense of the Present, Brains May Predict the Future'), first published by Quanta.

In March 2023, Maria Popova wrote an aticle in 'The Marginalian' ('Consciousness, Artificial Intelligence, and Our Search for Meaning') describing beautifully how Oliver Sacs covered this ground 30 years ago, in a readable but far more erudite manner.

The distinction between me and not-me is absolutely fundamental to the functioning of your body, and distinguishing between the two is not trivial: it can go wrong in various ways, resulting in a wide number of terrible problems which we collect under the heading of 'autoimmune' - examples of which include celiac disease, multiple sclerosis, psoriasis and rheumatoid arthritis.  There are hints that a number of other common problems may turn out to be autoimmune diseases, too.

in Is Consciousness More Like Chess or the Weather?, Brian Gallagher makes some helpful observations - including his description of consciousness and intelligence, and "The more you look into the brain, the less like a computer it actually appears to be."

See also a short article by Annaka Harris, The Strong Assumption, in which she articulates the theory that consciousness is a fundamental part of the physical world.

On a lighter note, I have just seen an advert for Magnum ice cream: the tag line is, "Not available in the Metaverse".  It nicely points out the fundamental difference between the virtual world and the real one: a digital representation of an ice cream is not an ice cream, just as a digital representation of a person is not a person.


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  • From Don: is the food in my body part of me?  Is my hair part of me - and am I less myself when I get my hair cut?


  • Thank you for posting a link to David Robson's recent article - I had missed that!

    To clarify my earlier remarks:  I accept that you make abundantly clear early on in your post, you describe the traditional Hebrew view that we see in Genesis 2:7 that  "God formed the man, the physical body, so you had a man but no life, and no mind. Then God gave this man life, and the man started to live – to breathe, to move, to think."   I agree that this is the standard reading of that text.   The issue is how much of that can be qualified by later understandings, such as by scientific discovery or by philosophical thought.   God's action clearly added some form of awareness - certainly of Him - but was it all of human consciousness?

  • I can accept that our bodies, not just our minds, are an important part of who we are. I’m quite attached to most of mine; I experience pleasure via some of it (not just that bit!), and some of it may give me pain or distress (fortunately not too often so far). I may not be the most athletic or most handsome specimen of humanity, but what I have is sufficiently a part of my identity that I won’t bother with plastic surgery even if I had the money. Conversely of course, some people have a very negative view of their identity because their body does not conform to a societal ideal.

    But surely all of what we know of anatomy suggests that it is the brain that processes these feelings. Without getting into the exact definition of “mind” or “soul”, they still communicate with our bodies via our nervous system. Someone in a “locked-in” vegetative state, which is probably the worst fate imaginable precisely because they cannot feel or use their bodies or communicate with the outside world, will be using their brain for whatever level of experience they are still capable of. Many of the most intense experiences in my life occur purely through my mind with my body playing very little part: I am sitting in an armchair reading or watching a film, or arguing with someone on the internet, or I am standing in an art gallery.

    Admittedly, the ancients believed that we experience emotions via our heart, or our bowels. During my nurse training I read a book by a psychiatrist supporting this view, but it is not something that has general acceptance. It is just possible that there could be something in that theory if we knew a lot more about the nervous system, but at present there seems little reason to think that emotions come from anywhere other than the brain – which does not rule out some kind of supernatural intervention in their origin. Acupuncture, where stimulation of one part of the body seems to affect another, anecdotally seems to work sometimes, in a way that cannot be explained as a placebo. If it does have a scientific basis the brain is probably still playing a part by functioning as a telephone exchange between the relevant nerves, but with so many neural pathways in the brain it will be difficult to prove this.

    This conversation derived from the link that Mark shared [below], where the atheist physicist Alan Lightman described how he once lay in his boat in the darkness on a calm night, looking at the stars, and had a transcendental experience in which he felt a part of something greater. He now describes himself as a “spiritual atheist”. (The term “spiritual” seems to have become used to describe any experience that cannot be explained by words alone and is not purely a bodily sensation; it includes religious experience but is much broader than that. We must discuss the use of the term sometime; likewise the term “transcendental”). Alan’s experience is clearly very important to him and it has made him a more rounded person with a broader perspective on the universe, but he has not become religious in any formal sense. Christians may say that God was talking to him through creation, as in Psalm 8, and this cannot be disproved. But the fact that so many people of varied beliefs or none have similar experiences, through nature or art or sex or adventure, possibly casts doubt on such a religious explanation. Essentially Alan Lightman was experiencing a form of sensory deprivation where the stars were all that he had to focus on. Sensory deprivation is known to stimulate unusual experiences. Michael Collins experienced something similar while he was on the other side of the moon, separated from all other human beings, in the Command Module of Apollo 11; again it made him a more rounded person but he did not become a Christian. People who experience total sensory deprivation in a dark sound-proofed chamber, whether as therapy or as a form of torture, can also have transcendental experiences, where their body is their only point of reference.

    So to conclude, this leaves us none the wiser about whether the search for the origin of human experience points to God or whether there is a need for God. I have noticed that Christians are more concerned about other forms of spirituality than about scientific atheism: many will say that Christian spirituality is the only valid type and that “the Devil has a counterfeit for everything that is of God”. A statement rather than a thesis. The human experience of spirituality enriches all who can be bothered to look for it, but it is far from clear whether it points to the Christian God or some other universal intelligence, or it may derive entirely from our neurons. Let’s just enjoy it while we still have neurons.

     Adrian Roberts

    15th August 2021.

    Fact and Faith: why science and spirituality are not incompatible -...


    Fact and Faith: why science and spirituality are not incompatible
    Physicist Alan Lightman’s purely scientific view of the world changed one evening looking at the stars in Maine – here’s why he now calls himself a s…
    • Adrian,

      Thinking a bit more... I would like to respond to your comment, "But surely all of what we know of anatomy suggests that it is the brain that processes these feelings."  Yes, and no.

      Your brain processes your interpretation of the feelings,  but feelings themselves surely originate outside the brain - feelings such as taste, pain and temperateure.  And the brain itself is affected by the hormones and other chemicals washing through your bloodstreeam, many of which are produced by your gut and the microorganisms living in it.  Your body affects how the brain thinks.


    • I fully agree with a lot of what you say here Adrian.  That humans need (and experience) more than the rationality that science can (and does) give us is not per se an indicator that any of that emotional response reveals truth about anything.  Perhaps it is simply that the way we have evolved (by definition a small step at a time) has meant that we find the myths about and responses to the vastness of everything around us compelling, reassuring, comforting and perhaps even necessary to survive. Perhaps this is the very essence of the importance of the arts. The arts can help us express the questions more eloquently, but I would be very reluctant to accept that they provide answers which can be taken as objective truth. Rather as science fiction gives us encouragement that the future may be intergalactic, at present that is purely imagination and hope. Much like religion.

    • Adrian - thanks for the response.  It's more than I can adequately respond to in a comment.  But just  a couple of quick notes ...

      I am arguing that you are a body, not just a brain; I'm not suggesting that the brain has no part to play.  The brain is vital for our identity and functioning, but it is not sufficient.  So I'm fine with most of your first three paragraphs; the bit I would question is where you say, "Many of the most intense experiences in my life occur purely through my mind with my body playing very little part".  I suspect that this simply means that you have very little awareness of the amount your body is contributing to these experiences.  One trivial example: you refer to standing in an art gallery: your body brought you to the gallery, no mean contribution; and standing is something of a miracle of bone, sinew and muscle in delicate relationship, responding to minute signals from your feet, eyes and ears, all contributing to this increbible balance which you have no conscious awareness of whatsoever.  And that is before we start to consider all the billions of things your body is doing just to keep you alive.  Very little part?  That's not the way I see it.

      As I mentioned on Thursday, I have been intending to write this for some time, so the article  by Alan Lightman (while very interesting and worth commenting on in another post) didn't really affect what I was saying.  Much more relevant is my recent experience of reading Sam Harris' book, 'Making Sense', where Harris discusses the nature of consciousness with David Chalmers.  He talks about the goal of 'uploading' ourselves onto faster (digital) technology, backing up your mind "so you don't need your meat body anymore", and perhaps doing it gradually, "one neuron replaced by one silicon chip at a time".  I have come across these ideas numerous times, and that is specifically what I was thinking about.

      As for Alan Lightman becoming spiritual but not religious - he is in good company.  I describe myself in the same way, and I believe that this is also a very good description of the Jesus we encounter in the Gospel narratives - although, not such a good description, I recognise, of the Jesus who was co-opted into the service of the Roman state some three centuries later.

      You tie this discussion in to the question of whether 'the search for the origin of human experience points to God', but I am not seeking to make that connection: in this post, I am simply seeking to articulate some basic points about identity and human existence (although, as Brian points out, not necessarily only human existence), partly in the hope of being able to reach a more solid starting point for future discussion.  My reference to God and to the Genesis story was simply to contrast the Hebrew 'animated body' understanding of humanity with the Greek 'trapped spirit' understanding - the distinction is (in my view) important, and does not depend at all on questions about the existence of God or the historical accuracy of Genesis.

    • I have often spent time thinking about this uploading thing.  Ever since reading a short story (author, title forgotten) many years ago about the possibility of transferring our 'self' from one body into another (e.g. stealing the body from someone stronger/better, or even I suppose of a different gender).

      The question that fascinates me is whether it is cut and paste or copy and paste.  And if it is the copy (how do you delete the contents of a brain anyway without killing it?) what happens to the two identies (orginal and copied). They would surely become two individuals, each going forward with a different set of experiences and exposure to ideas and events.

      What would it be like to have memories of a meat body?  And surely simply uploading would be insufficient - we would want uploading into an environment where we had agency, not just storage. So from that point of view I accept that our bodies are integral to who we are.  However I still see a major distiction between the CPU, the sensors and the activators.

    • Have you read: Altered Carbon, by Richard  K. Morgan -

      There was a Netflix TV series as well - it ran for two seasons:


      Altered Carbon
      Altered Carbon is a 2002 cyberpunk novel by the English writer Richard K. Morgan. Set in a future in which interstellar travel and relative immortali…
    • Sadly, I have neither read the books nor watched the TV series.  It looks fun.  And it seems to be describing precisely the type of future technology I had in mind when writing this piece.  Consciousness and sentience are attributes of living creatures: machines may be able to mimic them, but a machine is not alive even if, at times, it acts very much like a living creature.


    • Guardian article:  where the author of Altered Carbon Richard Morgan explains what led up to the book.

      Altered Carbon author Richard Morgan: 'There’s no limit to my capacity for violence' | Science fict…
      As Netflix screens his brutal body-swap novel, the writer talks about the anger – and the argument at a party – that fuelled its creation
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