BODIES
WHAT ARE WE MADE OF?
I am body entirely, and nothing beside.
Friedrich Nietzsche
Let’s begin by taking a quick trip around the human body. I’ll often call it ‘your body’, or sometimes ‘my body’, because this is not a matter of remote academic interest; I’m talking about what’s inside you and me, and how it is working, right now. I’m a scientist and, at least in this regard, a Nietzsche man, so I start by assuming that everything we do and think emanates, somehow, from this sophisticated biological construction. The eyes that are reading these words, the brain that is having thoughts in response, the facial muscles that are twitching involuntarily to signal agreement, amusement, puzzlement or irritation, the way those reactions are affecting the digestion of your last meal … all of this and much more adds up to who you are, right now.
So let’s have a look at what stuff we are made of, and how it is behaving. Unfortunately I can’t just ask you to look directly at what is going on, because we don’t have direct access. Much of what is happening inside us is not accessible to consciousness – you can’t feel the red blood cells being manufactured in your bone marrow as you are reading – so we will need the help of science to get a handle on what bodies are and how they work. I’ll briefly introduce a number of complementary perspectives.
You are a bunch of cells
What are little boys made of?
Slugs and snails, and puppy-dogs’ tails.
That’s what little boys are made of.
And what are little girls made of?
Sugar and spice, and all things nice –
That’s what little girls are made of.
Nineteenth-century nursery rhyme
Your body is the result of an evolutionary decision by living cells, as Benjamin Franklin put it, to hang together rather than to hang separately. The story of the evolution of multicellular organisms is the stuff of school biology these days, so a quick reminder will suffice. Somehow, around four billion years ago, some molecules came into being that had a curious property: they were able to reproduce themselves. More than that, they seemed bent on doing so. After a while, these replicator molecules had become able to create tiny homes for themselves that suited them and their reproductive tendencies. They wove membranes that enabled them to construct their own miniature ecosystems and so were able to keep conditions more or less to their liking. Millions of descendants of these first single cells – bacteria and microorganisms of many kinds – are swarming inside you and me right now. They live symbiotically with us, often to our benefit, and sometimes, when they make us ill, to our detriment.
Some of these cells set up working arrangements with even smaller cells. Mitochondria, for example, are simple unicellular life forms that have the deeply beneficial ability to generate energy, so our human cells welcome them as long-term lodgers, feeding and protecting them in return for a constant supply of fuel. Some of the cells learned how to divide, so they were able to replicate not just their DNA but the favourable cellular living conditions as well. And some of these tiny creatures discovered (by natural selection, over many generations) that, having split, there were advantages in sticking together, especially when they learned the art of specialisation, so that different cells could do different jobs on behalf of the whole community.
The survival strategy of forming collectives has both pros and cons, so not all multicellular experiments survived and not all cells decided to go down the path of living as a commune. An amoeba is vulnerable, but its needs are simple. If its world stays stable, it can easily get by on its own. It is low-tech and low-maintenance. But if the world changes, and what it needs stops floating by, there is little it can do. Big bodies, on the other hand, can move further and faster in search of food, can spot threats coming earlier, and can defend themselves more skilfully and vigorously. But they are expensive to maintain, and there is a great deal more to go wrong. Feeding becomes a military operation, requiring split-second timing of fork-raising by hands, mouth-opening by muscles, chomping by teeth and lubricating by saliva, swallowing by more muscles (making sure you also stop breathing at the crucial moment), squirting by digestive chemicals and churning by the stomach, and so on (you can imagine the rest for yourself). And communal living is not a breeze, as many of us discovered when we were students. Getting the right balance between ‘What is good for Me’ and ‘What is good for Us’ is often tricky.
Much of the detail of this evolutionary story is not essential here, but one thing is. The cells of which we are composed, individually as well as collectively, act as if they want to survive. This doesn’t mean they have conscious desires or preferences; it means they have a set of built-in responses to potentially adverse events that tend to neutralise or avoid the damaging consequences of those events. If the internal milieu of the cell goes off kilter, that by itself triggers processes that try to restore the balance. If their skin is punctured, things happen that have the effect of repairing the puncture. Cells that have these self-protective reflexes survive longer, and therefore have better chances of replicating themselves, than those that don’t. At our most basic level, we are purposeful – and intelligent. As Antonio Damasio says in his book Self Comes to Mind, ‘embodied knowledge of life management precedes the conscious experience of any such knowledge. [This] knowledge is quite sophisticated … its complexity is huge and its seeming intelligence remarkable’.1 (I just wonder why he felt the need to pull his punches by inserting that ‘seeming’.) I think this built-in disposition and capability to act in a way that meets your needs and concerns – especially as those concerns proliferate and your world gets more complex – is the very heart of intelligence.
You are a form of motion
Next to her the warm body [of her dog] shifted slightly, and she wondered if she was giving off minuscule tensions that disturbed sleep. She was trying to remain motionless, but that, as a kinesics expert, she knew was impossible. Asleep or awake, if our brain functioned, our bodies moved.
Jeffrey Deaver2
A while ago, I was sitting in the grand foyer of Sharpham House in Devon in the presence of a hundred or so other living beings and the dead body of Maurice Ash whom we had all known, admired and loved. I was watching his body intently, and I saw him take a breath. I actually saw his chest move. Of course he didn’t really breathe, but my brain so rebelled at the utter stillness of the body that it overrode the facts and, for a moment, insisted on bringing him back to life. Complete stillness is incompatible with life: it is anathema. A child that is born still makes one revolt at the wrongness of it.
The body isn’t a thing, it’s an event. We exist by happening. When we look in the mirror, we see a familiar object looking back. When we look down, our legs look and feel solid enough. But we know that if we stop happening, we quite quickly start to fall apart. If we lock up the house and go on holiday we imagine it will just stay put, but not so the body. Even when we are asleep neurons are firing, cells are developing, bladders are filling, blood is pumping, lungs are breathing, legs are twitching and throats grunting. In a thousand ways, large and small, we are squirming and wriggling the whole time. Moving is not something we do from time to time and rest in between. Rest is itself a form of motion. There is special circuitry in the brain, called the default network, which starts up precisely when we have nothing urgent to do. On the micro level, we are constantly abuzz with activity.
If we don’t do things, we don’t survive. Human bodies, like their individual component cells, are constantly replenishing their nutrients. In order to provide our cells with the necessary raw ingredients, from time to time we have to get up and go to the fridge or phone for a pizza. To be alive is to need supplies. And to get them, we need to be mobile. So we have evolved to be active at the macro, behavioural level, as well as at the micro. In the long run we will lose the battle for survival, but until death our complex, multicellular bodies, like the single cells from which they are made, act as if they want to keep on living – till we have done our reproductive duty and more. Our bodies’ chief priority is action in the service of their survival, well-being and reproduction. As neuroscientist Daniel Wolpert puts it:3
While sensory, memory and cognitive processes are all important, they are only so because they either drive or suppress future movements. There can be no evolutionary advantage to laying down childhood memories or perceiving the colour of a rose if it doesn’t affect the way you are going to move later in life.
In short, we are restless, active, proactive creatures, full of hopes, desires, fears and expectations; bundles of projects, short term and long term, worthy and unworthy, humdrum and grand. As I sit here, I am interested in what the boys on the beach are doing, shifting my posture to get comfortable, thinking about how to cook my chop for supper, wanting to finish the chapter, searching for the right word, remembering I need to water the plants on the balcony … and on and on. Biological intelligence can’t be understood unless it is built on this core concern with matters of action and desire.
As I said in the last chapter, we aren’t like computers: machines happy to wait patiently until they are switched on and told what to do. We are constituted by a fluctuating (and expanding) portfolio of inherent concerns, and constantly animated by physical attempts to address those concerns. We might note that the word ‘mind’ itself still carries, in everyday speech, strong echoes of that motivational impetus. To mind is, at root, to care. If you mind about the result of the match, you don’t just think about it, you are concerned about it. It matters. You mind terribly – as opposed to your partner who may not mind at all. A child-minder is not just conscious of the toddler; that awareness is imbued with concern. We mind, in the sense of care, before we are minds, in the sense of possessing organs of intelligence. Fundamentally we are not designed for thinking, philosophising or solving cute logic problems against the clock. Reason and debate are themselves tools that evolved to support deeper biological agendas.
The reason we have a brain is mainly to figure out and implement the right movement to make, given our current concerns, and this is a complicated problem. Animals that move have brains; those that don’t move, don’t. There are a few animals, like the sea squirt, that start out as movers – they swim around – and so possess a basic brain for coordinating their movements. After a while, however, they decide it would be less effort to spend the rest of their lives as plants, so they find a good spot, put down roots, and survive on whatever comes their way. Having no further use for their brain, they eat it. (As the old academic joke has it, this is not unlike what happens when university professors finally get tenure.)
You are a flexible cage
The physical manifestation of the body is primary. The stuff of intelligence has evolved in conjunction with that body, and is a modulator of its behaviour, rather than a primary and central control system.
Rodney Brooks4
The first intelligent thing that mobile creatures have to have is a body that moves in the ways they need it to. Some just have little tails they can swish around, and others are able to shrink away when prodded. But the lifestyle of our multicellular forebears needed more speed, more strength and more precision than that, so they evolved a skeleton. This is a semi-rigid but partly elastic cage made of bones that protects and supports the soft organs within. It has joints to which limbs are attached. Bones are connected to each other by strong bands of elastic muscles which can contract, causing the bones to move relative to each other. Muscles are attached to bones by tendons and bones are connected directly to one another by ligaments. Evolution has adjusted the lengths, weights, arcs of movement and elasticity of this articulated cage so that the skeleton as a whole can move quite smartly, even without much input from a brain.
When you were young, you might have had (as I did) a simple toy that would walk by itself down a slope. If you got the slope at the correct angle, it would walk steadily down without either stopping or falling over. It did so just because of gravity and the mechanical way it was constructed. It would start to topple forward, but that toppling freed one of the legs to swing forward like a pendulum. Still toppling, it would stand on the first leg and thus free the other to swing forwards, and so on. Now, if you want to make a version of that toy that would walk on the flat, you have two options. One is to start from scratch and design a coordinated set of sensors and motors to move the legs in turn. For that you would need a small brain. Alternatively, you could design a way of getting the toy to tend to topple again – perhaps by giving it a long and heavy nose – and then rely on the same cheap, mechanical pendulum effect of the legs to keep it walking. You might have to adjust the parameters a bit, but it would work.5
Rolf Pfeifer and his colleagues at the Artificial Intelligence Lab at the University of Zurich have explored the potential of the second strategy in some detail.6 Instead of loading the intelligence into a kind of brain that controls the leg movements ‘from the centre’, they have shown how much of this intelligence can be embodied in the physical make-up of the body – if you get all the weights, resistances and ‘springs’ (muscles) right. The figure below shows Puppy, one of their four-legged robots built on these principles. Puppy walks on the flat in a lifelike way, but it has no brain: no organ of central coordination.
To get more sophisticated behaviour like running uphill, or walking on uneven ground, you do have to introduce some brain-like control, but only to moderate the behaviour of the ‘intelligent skeleton’, or to kick it off: not to orchestrate everything. A robotic relative of Puppy, called BigDog, is able to walk on slippery or muddy surfaces, for example, and can pick its way over a heap of rubble without falling over. (You can see BigDog in action at www.youtube.com/watch?v=cNZPRsrwumQ. It might better be called BigFly as the go-cart motor that drives it along emits a very loud un-canine buzzing noise.)7
These K-9s illustrate an important characteristic of how real bodies work; a good deal of the apparent intelligence of the mind and the brain is distributed around the physical systems of which the body consists. Getting Puppy and BigDog to walk may seem somewhat trivial compared with the intricacies of mind and body for which the accolade ‘intelligent’ is usually reserved, but we will see how similar principles of embodiment continue to apply as we scale up. Pfeifer sums up this important insight thus:
Behaviour is the result of an agent interacting with the real world, which includes not only the agent’s neural system but its entire body: how the sensors are distributed, the material properties of the muscle-tendon system and the joints, and so on. This collection of interdependent mechanisms [we can call] the agent’s embodiment.8
The idea that intelligence can be embodied in physical structures, and that such structures can therefore take some of the strain off minds and brains, is a key one in the science of embodied cognition.
*****
If we are trying to creep up on the idea of ‘intelligence’, we cannot leave the subject of the musculoskeletal system without saying a word about the human hand. Without the hand we would not be able to make or use even the simplest tool, and without tools, we would demonstrably be a whole lot less smart than we are. As Raymond Tallis puts it, in typically droll fashion: ‘If Adam and Eve had been expelled from Paradise with paws instead of hands, the history of the human race would have been unimaginably different.’9 Where would we have been without our ability to grasp, caress, pluck, catch, pull, twist, pinch, prod, punch, rub, scratch, tap, drum, throw, write, squeeze, tickle and dozens of other manually clever things?
Undoubtedly the human hand requires a sizeable brain to accompany it. Indeed, many, like Tallis, have argued that the evolution of the human hand (as opposed to the paw) may well have been one of the principal drivers for the evolution of the brain. But, as with the example of walking, we must not assume that the hand is just a highly articulated but essentially passive tool that depends on an intelligent brain to tell it what to do. Some of the ‘joint intelligence’ that the brain+hand so obviously possesses is embodied in the hand’s physical composition.
The hand has a thumb that can swivel, and which is also of just the right length to enable it to ‘oppose’ the first finger. This enables us to pinch and grasp. At the base of the thumb are unusually strong muscles, so that the precision of the grip can be backed up with considerable power. We have flexible, jointed fingers that can (and do) curl up, and also move independently of each other (to some degree). We have nails instead of claws, and these provide a protective backing to fingertips of extraordinary sensitivity, capable of detecting tiny changes in texture and resistance. We have ridged skin on our hands that increases friction, providing increased grip for larger objects. The skin is also capable of being deformed and compressed like a cushion. And the whole constellation of small bones, muscles and tendons means that when the hand starts to close around an object its physical construction will automatically adapt its grip to match the shape of the object – without any help from eyes or brain.
Japanese robotics researcher Horoshi Yokoi has created a prosthetic hand with many of the same physical properties as a real one, and has shown how it can grasp a wide range of objects very successfully without complicated control. You just tell the Yokoi hand to ‘close’, and physics does the rest (see Figure 3). This is good news for people who have prosthetic hands. Their brain can produce motor commands that can be picked up on the surface of their skin by an electromyograph (EMG) and converted into control signals for a robotic hand. But EMG signals are very ‘noisy’ and therefore control of a conventional prosthesis, which requires precise signals to tell it what to do, is poor. The Yokoi hand performs much better – and is a lot cheaper.10
When we come back to the human body as a whole, we find another set of problems to do with general coordination. The musculoskeletal system has many movable parts, and they must work in concert. Some of this needs delicate central orchestration by the brain, but again the brain modulates what the body is doing rather than having to design it from scratch. One of the ways it does this is through the physiological tremor. As far back as the 1880s, it was known that the entire muscular system of the body was constantly vibrating at a rate of around 10 cycles per second. When any part of the body moves, its activity is overlaid on this tremor, and this helps the rest of the body to stay coordinated – just as a pair of dancers can be better ‘coupled’ when both are listening to the same music and their movements are tied together by a common beat.11 This example reinforces two of our main points in this chapter: the intrinsic activity of the body, and the way in which this inherent activity contributes to the overall intelligence of the whole person. The brain cannot be properly understood except as one element of a larger system that includes the body.
You are your organs
Inside and around the skeletal cage, and beneath the protection of the skull, are clustered the major organs, substances and systems of the body. Each of these carries out functions that are necessary to keep us alive. Life, even as a multicellular being, is precarious, made possible only when a large number of conditions are met simultaneously within the body.12 The body can only tolerate small fluctuations in a whole range of its parameters. For example, the composition of various gases inside us, the acidity of the inner fluids that constantly bathe our cells, and the temperatures that are conducive to the chemical reactions necessary for survival can vary only within narrow limits. The major organs of the body are each designed to keep track of a subset of these variables, and have ways to bring them back to optimal values if they begin to wander off. When energy levels flag, we have to locate food, get it inside us, convert it into the universal currency of energy, the ATP molecules, get the energy molecules distributed to wherever they are needed, and get rid of the waste products. The internal division of labour means that clusters of cells devote themselves to these different but interlocking tasks, thus constituting various ‘centres of operation’, which we carry around inside us.
If we are to uncover the intelligence of the body, we will have to overcome our Platonic squeamishness and dive into our moist innards. A venerable Buddhist meditation may help here. It is called Patikulamanasikara, which roughly translates as ‘reflections on repulsiveness’ – and it is that attitude of anxiety about and disgust at our own substance we need to challenge. Just because our insides are dark, slimy and sometimes smelly, that doesn’t make them ‘dirty’ or ‘bad’. Disgust at our own insides only arises within the historical framework we discussed in the previous chapter. The meditation lists the physical ingredients of the body. They are (in slightly updated form):
Heart, lungs, spleen, lymph nodes, pancreas, kidneys and liver
Brain, eyes, ears, nose and tongue
Skin, flesh, bone and bone marrow
Stomach and the rest of the digestive system
Hair (in various locations), nails and teeth
Skin, tendons, ligaments, cartilage, gristle, diaphragm and nerves
Faeces, urine, sweat, grease, fat, semen, snot, phlegm, saliva, tears, blood, lymph and pus
Monks are encouraged to (as one handbook puts it) ‘contemplate the body … as being full of many impurities’ – but the point is not to cultivate that reflex of disgust but to learn to replace it with an attitude of polite interest. Innards R Us; they are our family; they need only make us anxious when they become visible. Concern when those insides spill out as vomit or blood is evolutionarily entirely appropriate. But if we are to really understand the body, and learn to be it, we have to befriend it, locks, snot and marrow.
When we think of our insides it is often the stable, visible structures we focus on – brain, heart, lungs, kidneys, liver, intestines and so on. Because they can be readily dissected out of the body, they have tended to be treated in terms of their most evident functions, and understood through simple analogies. The lungs are like bellows; the heart is like a pump; the stomach is a food processor; the kidneys are filtration plants for the body’s fluids; the liver is a pharmaceuticals factory. And indeed they do perform these functions, and much besides. Each is ‘intelligent’ in its own right. But when we come to think about the intelligence of the body as a whole, it is the way the different organs and elements communicate with each other – how the intelligent whole becomes more than the sum of its parts – that is of more interest.
Take the heart, for example. In 1991, Harvard physiologist Ary Goldberger reported an intriguing finding. As we have seen, the different bits of the body are generally thought to have an ideal level of functioning, and if they are perturbed from this – if blood sugar falls below this level, or if blood pressure rises – then they start to behave in a way that gets them back to the ‘ideal point’. But how precisely defined is this optimal level? Is it a point, or is it a range? It has usually been assumed that it is the former; if everything is fine, there is no need for the heart rate, for example, to vary at all. The healthy, happy heart should have a constant beat. But Goldberger found that it doesn’t. ECGs of a normal heart show that the rate varies quite a lot when there seems no reason for this, and it does not vary in any obviously regular way. Hormone levels in the blood serum of normal, healthy people also fluctuate much more than seems necessary. So what is going on?13
The answer seems to lie in the fact that the heart, if it is to stay healthy, needs to keep talking to the rest of the body. It is not just doing its thing in isolation. The heart actually has its own little brain, which enables it to keep in constant communication with the lungs, the liver, and the rest of the central nervous system. There are inputs from the sympathetic nervous system that normally increase blood pressure and/or speed the heart rate up, and other inputs from the parasympathetic nervous system that generally lower Blood pressure (BP) and/or slow the heart down. And there are outputs from the heart that send messages about its current mechanical, electronic and chemical state to other organs and upwards through the autonomic nervous system to the brain stem, and thence to the brain as a whole. In between these incoming and outgoing neurons, there is the heart’s own web of internal communication neurons that relay the news that is coming in and modify the information it is broadcasting. The heart is an inveterate tweeter.
This ‘little brain on the heart’, as Canadian researcher Andrew Armour calls it, uses all this activity to modulate the heart rate, and other parameters, on a beat-by-beat basis.14 In other words, the healthy heart beats somewhat erratically because it is in constant resonance with the wider body of which it is a part. Homeostasis prescribes not an ideal ‘sweet spot’ that the heart is forever trying to return to, but a ‘sweet zone’, a range of values, within which it must have the freedom to move around. And indeed, one of the characteristics of the unhealthy heart is a loss of this elasticity, and an increasingly regular heart rate. Goldberger has found that sudden cardiac arrest – a fatal heart attack in an apparently healthy heart – is very often preceded by an increase in the regularity of the heartbeat. Lacking its usual inherent flexibility, the heart cannot respond as effectively when the conditions around it suddenly change. It is as if it has stopped listening to the radio, so news of an impending tsunami goes unheeded and the heart is therefore caught unawares.
Other bodily systems also have brains of their own. The digestive system contains its own nervous system that enables it to regulate its responses to inputs of various kinds, even when it has been disconnected from the brain and the spinal cord. Evolutionarily this is not surprising. We were digestive tubes long before we developed separate brains – as each one of us was, once upon a time, in the womb. The body has been well described as a dense city built along the banks of a busy waterway, the alimentary Grand Canal. Goods arrive at landing stages, fish are caught along the banks of the canal, and waste is discharged downstream. Regulating the transactions along the margins of this tube is a complex business: there are more than a billion nerve cells in the small intestine alone. Many are concerned with the activity of the gut itself, for example in maintaining healthy relations with the vast army of bacteria that have set up camp principally in the lower gut. But many are also in constant communication with the other organs and regions of the body, including the brain.
You are biochemical soup
As well as the solid organs, you are composed of other systems that cannot do their job unless they are floating around, permeating the body as a whole. The circulatory system is one, carrying the energy-giving red corpuscles of the blood to the remotest corners of the empire. But the fluid of the blood, the plasma, along with the lymph system, also carries a host of chemicals that help with self-defence and self-repair. The liquid immune system carries the so-called white blood cells, technically the lymphocytes, which are a kind of ‘homeland security’ service, constantly checking the papers of the molecules and microbes they meet to enable the body to tell friend from foe. Each lymphocyte has a big sticky molecule, an antibody, attached to its surface, which is like a Wanted or Missing Person poster of the particular friend or foe for which it is on the lookout. When it finds a match, it either gives it a hug or performs a citizen’s arrest. The lymph nodes dotted around the body are local jails and interrogation centres for any undesirables that get picked up.
The traditional image of the immune system is as ‘civil defence’, but it is much more than that, because the friendly interactions turn out to be at least as important as the hostile ones. The lymphocytes are not just the secret police; they are a vital mobile throng of meeters and greeters, exchanging information and keeping the different regions of the body literally ‘in touch’ with each other and with the whole. The Chilean immunologist Francisco Varela, whose work has been seminal in the development of the whole area of embodied cognition, says that the immune system is really there to keep knitting the various specialist groups within the body into a single somatic identity.15 When the immune system spots intruders, it has a sophisticated capacity to deal with them. But this is only how it responds to emergencies. Most of the time it is monitoring and maintaining the body’s sense of coherence and identity, and this is key to how we function in the world. Mice that are raised in completely sterile environments still develop a nearly normal immune system, for example, because, even without the threat of disease, the immune system is essential. It thus has to keep up a constant dialogue with the brain. As Varela says: ‘A more sophisticated psychosomatic view will not develop unless and until we understand that the immune system is a cognitive device in itself.’ It is part of our intelligence.
Intermingled with the lymphocytes and erythrocytes (red blood cells) floating around the canals and marshes of the body’s interior are a host of chemicals that help to regulate what is going on: the ingredients of the endocrine or hormonal system. They include neurotransmitters and neuromodulators – chemicals that regulate the firing of neurons – such as adrenaline, acetylcholine, dopamine and serotonin; sex hormones such as oestrogen and testosterone; and a wide variety of short amino acid chains called peptides, for example insulin which regulates the metabolism of carbohydrates and fats; cortisol that affects the way the immune system responds to stresses of various kinds; and oxytocin which alters mood, especially in relation to caring and intimacy. These hormones are manufactured in various glands and released into the bloodstream, into the lymphatic system or directly into the free-flowing fluid that surrounds all the cells. All of these floating chemicals carry news, advice and instructions. Hormones, for example, have a specialised molecular ‘smart card’ that will only ‘work’ when it finds the corresponding ‘hole-in-the-wall’ slot embedded in the wall of one of the cells which it happens to be floating past. When a fit occurs, the cell is triggered to change its behaviour in a particular way.
So these organs and systems are not functionally separate from each other. When I was a student, I was taught that the body had three distinct systems, the endocrine system that circulated regulatory hormones, the immune system that fought infection, and the nervous system that sent electrical messages around (of which more in the next chapter). But not only has our understanding of these systems developed enormously over the last thirty years; we now know that it is much more accurate to see them not as independent and parallel, but as aspects of a single system that looks after many complementary aspects of our well-being.16
The nervous system is as much a chemical system as an electrical one. Neural impulses are triggered by microscopic changes in chemical concentrations, and regulated by all kinds of chemical neuromodulators, which may originate in a wide variety of organs and tissues. The constant neurochemical tweeting of the heart is just one example of the constant cross-talk between different bits of the body. The lungs and the heart are talking to each other via the hormones and antibodies coursing through the pulmonary artery. The immune system penetrates into the innermost recesses of the digestive system, and interacts with the neurotransmitters in the gut’s own nervous system.17 And so on. In addition, we might add that all of this activity is affected by the dynamics of the muscles and joints. Large-scale physical activity – from the runner’s ‘endorphin high’ to the soothing release of oxytocin in the suckling baby – serves to regulate and coordinate what is going on at more microscopic levels.
You are a CADS
What this all adds up to is radical shift in the way we look at our bodies. For centuries we have taken the vocabulary of medicine and used it to think about how our bodies are structured. But it turns out that the language of distinct organs and systems does not do justice to the coherence and interwoven nature of the body. More than that, it blinds us to the essentially systemic nature of our bodily selves. Western medicine has made huge progress by conceiving of the body as an assemblage of parts, each of which can be treated separately when ‘it’ malfunctions. But we are not built like clockwork, and conventional, so-called allopathic medicine is only just beginning to recognise maladies that cannot be localised to a single source or cause.
Of course there are many other medical systems, such as homeopathy, acupuncture, and those of traditional Chinese herbalism or Indian Ayurveda, that do recognise the intricate interdependencies of the body. But they are often such a tangle of accreted folklore (some of which bears scientific scrutiny and much of which doesn’t) that it is impossible to sort the demonstrable truth from the passionately held and anecdotally supported belief. (And, of course, the placebo effect is still worth having.) Out of the kind of work that I am describing here, a scientific framework for understanding holistic effects may well emerge, but hybrid disciplines like psychoneuroimmunology are still in their infancy.
But this is not a book about medicine. The point I want to emphasise here is the more general one that our bodily selves are systems – technically, Complex Adaptive Dynamic Systems, or CADS for short.18 Systems theory is one of the foundation stones of embodied cognition, so it is worth having a quick look at its main features. In many scholars’ hands, systems theory quickly becomes pretty technical and often mathematical, so I am going to avoid many of these intricacies here and just try to give a flavour of the approach. I’ll call a system in the technical sense a System to distinguish it from more everyday usages (for example, when I mentioned different medical systems in the previous paragraph). A System is a constellation of processes that are themselves Systems: I’ll call these contributory Systems, Sub-Systems. When a bunch of Sub-Systems get together and interact with each other in complicated, reverberatory ways, they can create a larger System that seems to have a kind of stability and integrity. It may look like a reasonably stable structure, for example, though this kind of solidity is maintained only through constant dynamic interactions of the Sub-Systems.
A termite colony or a beehive is a System. Hundreds of small creatures – Sub-Systems – are doing their own thing, but they are also interacting through local messages. These kinds of small-scale interaction can lead to the emergence of coherent ‘swarm intelligence’. For example, a termite mound is like a Gaudi cathedral, a complex architecture of pillars and vaults, which looks as if it would need high-level thinking and lots of meetings to accomplish. But that’s not how termites do it. Individual termites like to make little mud balls that carry a chemical scent, and to roll them around. They deposit them where the scent is strongest – which leads them to create piles of mud balls that compact together into pillars. If two pillars grow up near each other, a termite carrying its ball up one pillar will get a waft of the scent from the adjacent pillar, and so tend to deposit its ball on the side of the pillar nearest to its neighbour … and after a while, the two pillars lean together and form an arch. No termite has a plan. No individual knows about arches or intends to build one. Yet it is hard to resist the idea that there must have been intention or design somewhere. The System-level intelligence emerges naturally from a lot of Sub-Systems talking to each other and following their own local rules.19
The body is a System in the same way. Its minute elements respond to each other in a way that makes coherence, and the appearance of ‘purpose’, emerge. Each of the Sub-Systems behaves as it does partly out of its own nature, so to speak, and partly as a result of the interactions it is taking part in. The ‘bits’ are in constant resonance with each other, and these resonances modify their apparent nature. The bits may seem to be anatomically distinguishable, but they can’t be dissected out and expected to behave in the same way. The heart that marches only to the beat of its own internal drum is a sick heart, remember. In a System, any apparent boundary or membrane that seems to mark the limits of a Sub-System isn’t a barrier or a stockade; it is a site of constant, vital interaction. If nations retreat into protectionism, and international trade stops, then life within the national borders must adapt. Under siege, life has to change or it stops.
Now, what is sauce for the Sub-Systems is sauce for the superordinate System – because the System is also a Sub-System within a wider set of forces and interactions. As my heart is to my body, so my body is to the world around me. So each System is only the way it is because it is an aspect of a Super-System. The heart beats as it does because it is listening to the rhythms and cadences of the gut and the lungs. I am as I am because I am constantly being licked into shape by the air I breathe, the food I digest, the birdsong in the garden I can hear and the shifting quality of the relationship I have with my wife. I am different when we are not together, and so is she. Judith and Guy are not identifiable ‘players’ in this relationship any more – when we are together, there is only Judith-in-the-context-of-Guy and Guy-in-the-context-of-Judith. As I move around, the nature of the Super-System around me changes, so I am always Guy-in-the-context-of-something. The relationship has emergent qualities that are not reducible to separable qualities of us as individuals; and we as Sub-Systems are constrained and shaped by the Super-Systems of which we are currently elements. There is no ‘But who am I really?’ because if I were truly isolated from all the big Systems around me, I’d be dead (or dying). Everything in the living world is a Midi-System, a transiently stable yet always changing configuration of material in motion.
So from the CADS perspective, the human body is not a noun, it’s a verb. We aren’t like billiard balls that meet, collide and ricochet off unchanged. We are confections constantly being whipped up by a combination of the Super-Systems in which we are participating and the Sub-Systems of which we are composed. We are like whirlpools and eddies in a river that cannot be taken home in a bucket. We are like clouds and waves, constellations of processes that, for a while, have the appearance of being ‘things’. We are like gyroscopes or spinning tops that have stability, actively resisting being knocked off course only because they are constantly being spun. If the process of spinning is not maintained, the apparent ‘desire’ to resist being perturbed disappears. The coherence of bodily structure and behaviour reflects the constant internal resonance of all their ingredients with each other – and with the wider set of Systems within which they are embedded. Out of all this dynamic reverberation emerges a person making a sandwich, and reading a brochure for a new car while eating. Or a baby yelling in the night. Or a heptathlete hefting her javelin.
As we find out more about how bodies are constructed, and how they really work, we cannot help but be impressed by their intelligent bioengineering. We have seen that, without a brain, our bodies are able to do some pretty sophisticated things. So the obvious next question is: why do we have brains?