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 traditional Hebrew understanding was that a person is 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.

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. 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, gut, kidneys and bladder, and they are affected by the proteins and other chemicals carried in my blood from glands all over the body.

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.


Here is a link to this blog as a PDF: You Are Not Your Brain.

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 I make in this piece.  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."  And it 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.

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    • I completely agree with that distinction between the Hebrew and the Greek understanding of soul and being.  I first encountered the idea of Nephesh in this short video from the Bible Project:

      I would be interested in people's views on the above.

    • So if the Nephesh is the body/physical being, resurrection of the cremated is a recreation rather than a resurrection?


    • Mark,

      I think your question is reasonable, but it presupposes a different understanding of what the Biblical writers and modern theologians understand by these terms - which is entirely understandable, given that the mechanics of resurrection are nowhere considered in the Bible, and any speculative discussion of the mechanics tends to be very academic and abstract.

      My own understanding is that resurrection is always a recreation, whether it is someone who was cremated or someone who was buried.  Resurrection is about the person living again in a physical body, but a physical body which is significantly different from the bodies we are presently familiar with.  Jesus' resurrection body could light a fire and cook fish, but it could also appear and disappear.  The promise of resurrection is that we will be like Him, whatever that means.  It certainly is not about the atoms and molecules of the old physical body somehow being brought back into their previous arrangement.

      This promise of resurrection is quite different from the miracles described in the Bible where people are brought back to life a short time after they have died: in each of these cases, the old body is clearly re-animated (which, I assume, involves some creation or re-creation) and, fairly obviously, the re-animated body eventually dies again.

  • Great article.   I need to give a longer response - but basically, I agree that the human being comprises mind, body and soul - all three domains.   Our brain is involved with all three, I would say.   My main issue is that consciousness, our own self-awareness of ourselves (i.e. conscious awareness) may not be entirely unique to humans.   As a Christian, I fervently believe that all of us humans are "made" in the Image of God and that this universally gives everyone cognisance of spirituality i.e. awareness of God, quite irrespective of creed, race or education.   I don't identify spiritual awareness with conscious awareness - it extends it.

    This issue is all going to get far more pressing, once Animal Sentience is passed into UK law:   Just to be clear, I support this entirely (long overdue) - but the starts to bite hard when we think about human food supplies - can we still eat animals of any kind? - and what about providing food for animals, now we accept they have sentience?   What rights do sentient animals have?  What is humanity's duty of care for sentient animals?   And how do you make it obvious when an animal is sentient?   What is an appropriate scientifically sound test for sentience?

    Have you seen:  Am I just my brain?  by Dr. Sharon Dirckx  (   A short review is here

    A shameless plug:  Sharon Dirkcx is speaking on this topic on Friday, 21st January 2022  in the recently announced CiS Bristol lectures for 2021/2022.


    Animals to be formally recognised as sentient beings in UK law
    Set of government measures will include halting most live animal exports and a ban on hunting trophy imports
    • Brian - shamefully, I confess that I have not seen Dr Dirckx' book - thanks for pointing it out; and I was unaware of the event next January.  But looking forward to it now!

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