14 DAY TRIAL // One of the most common and wide-spread ideas is the myth of the mind / body separation, the idea that the body is a sort of senseless machine controlled by the mind which is understood as a sort of ghost that lives inside this machine. This idea is so common that it is amazing to find out it is also a relatively new idea. In a certain sense it is only four centuries old and its inventor is Descartes. Or, if you prefer, Descartes is the one that has popularized it in such a convincing way that the idea has gained the almost universal acceptance it enjoys today.
What was before that?
It is interesting to read Ancient Greek or medieval philosophers and to see how they managed to get along without the mind / body separation. For example Aristotle struggled to understand how visual perception worked and came up with two different theories. The major difficulty he encountered stemmed from the fact that he was not equipped with the distinction between abstract information on one hand and the material that carries the information on the other hand. Historically, this distinction between information and information support is a consequence of the mind / body separation (as it is analogous). Some might see the mind / body separation as a consequence of the information / information support distinction, but historically it was the other way around.
So, Aristotle tried, at first, to describe visual perception as if it was a kind of phase transition: light came into the eye and "condensed" into the material of the eye (water); when it transformed into water it mixed with the eye and this is how, supposedly, the eye learned about the external world. At the time there was an ongoing controversy regarding the issue of whether we see because light enters into our eyes or because our eyes emit something that reaches for the objects. Aristotle argued in favor of light entering the eye with arguments such as: when you turn off the light you cannot see.
However, it seems that Aristotle wasn't satisfied with this theory. The problem was how could the sensation of a large, extensive, three-dimensional world form out of the tiny and very localized phenomena that happened inside the eye? This dilemma, you see, appears precisely because he didn't have the distinction between information and the information carrier - he could not understand that light carries something, "information", into the eye, and that the brain then "processes" the information (Aristotle thought that the function of the brain was to maintain the body temperature constant!). Aristotle's solution was to assume that, after all, the eyes do emit something: these eye-rays were supposed to mix with light on the surfaces of various objects; the individual had the sensation of an extensive and large world due to the extension and direction of these eye-rays reaching for various objects and mixing with light there. This theory also accounted for the fact that you can't see in the dark.
The mind / body separation is now an intrinsic part of Christian beliefs so you would expect that famous medieval theologians such as Thomas Aquinas (who still is the basic reference for the Catholic Church) would know something about it. Not so. In fact one of the most important things Aquinas was underlining was that God was intrinsic in everything. The soul was not something distinct from the matter of the body, it was an essential property of the body. In fact Aquinas did little else than to translate Aristotle into Christian terminology. So for example he couldn't explain a sensation by assuming that information was sent from one place to the brain in order to be interpreted, he had to assume that the matter itself sensed the sensation.
This is quite intuitive actually, it's only our education that makes it sound silly: after all when you touch something with your finger you feel the sensation in your finger. It is quite a revolution to say that the sensation actually happens somewhere else (in the brain). This revolution was started by the work of Descartes. It is amusing to read Descartes himself and to see how he treats certain ideas that are common sense for us as if they are very controversial. At the time they were controversial!
Other cultures such as the Hindu or the Chinese also used to have an Aristotelian-like view. For example according to the Hindu religion God is the universe itself and it is thus part of everything. God is supposedly playing a hide-and-seek game with himself, hiding under the form of everything that we see, including ourselves, and the purpose of this universal game is for him (or for us for that matter, as we are him) to rediscover or recreate that wonderful unity. When the game will reach its end and the unity is recreated, it will start again (maybe in a different form).
One of the major consequences of the mind / body separation was the distinction between the universe and its "laws of nature". Before that the very idea of supernatural was impossible. For medieval people witches for instance were not "supernatural"; they were very much a part of everyday life. Studies of ancient Greek culture also reveal that the supposed "rationality" of ancient Greeks is in fact much overrated; they lived in an environment of constant "miracles". But they didn't consider these "miracles" as such, they thought they were normal. The same was true about the Romans. For example one of the reasons why Christians were sometimes abused in the Empire was that they refused to take part in various rituals that were supposed to protect a city from disease or disasters; for the Romans such "magic" rituals were in fact normal tools for influencing nature, in the same way as vaccines are normal for us, and, because they refused to take part, the Christians were seen as a sort of traitors that were summoning disasters.
The birth of the homunculus
The theory Descartes put forward - the "dualism" between mind and body - solved a great deal of mysteries. For the first time people started to get some clues about the workings of phenomena like perception and scientists adopting Descartes' view could start to see themselves as separated from the things they were studying. They were suddenly gathering information about stuff and they were organizing this information like some sort of librarians of nature - distinct from nature.
The predecessors of modern scientists, people like the alchemists, saw themselves in a completely different light. For the alchemists all the chemical experiments they were performing also hold promises about spiritual matters. The alchemist was very attached to his work, it was something highly personal which supposedly was about to bring a personal transformation - the same material that would transform lead into gold would also have the power to make you immortal. (Some of the first modern scientists, such as none other than Newton himself, were partially still receptive to the alchemists' point of view - so receptive actually that most of Newton's works concerned alchemy; physics was like a hobby to him.)
But Descartes' theory came with its set of problems that finally, in the 20th century, couldn't be ignored any longer. The most obvious problem was how exactly do mind and body interact with each other? If they are so radically different how do they manage to influence one another? Descartes himself wondered about this and, not surprisingly, after four centuries the question still remains unanswered.
Another nice problem is the homunculus problem: The Cartesian explanation of perception involves the sense organs gathering information about the world and then the brain that interprets the information (and somehow the mind, or the "spirit" or the "soul", is impacted by this interpretation and feelings and thoughts appear). But how does the brain interpret the information? If the information is gathered and presented to the brain does the brain have its own sense organs that perceive this information?! It is as if it is claimed there is a little man inside your skull (called the "homunculus") that watches on a TV screen (called the "Cartesian theatre") what your sense organs transmit. And then, is there an even smaller homunculus inside the homunculus' skull? And so on ad infinitum?!
The homunculus is created by the mind / body separation. It is a metaphorical personification of the link between the two "substances". Aristotle wouldn't have such problems (he had bigger ones). In the image (credit: Bryan Crockett) the homunculus looks like that because we have different sensitivity for various portions of our body (e.g the hands, the lips or the penis are much more sensitive that the abdomen).
Related problems
The mind / body separation is analogous to other such separations. But the mind / body problem is more difficult to solve than these other problems and one can get valuable clues from them.
For example we have the separation between the "hard facts" and the "formal theory". The theory is supposed to be purely abstract (the realm of the mind), while the facts purely empirical (the realm of matter). In order to "give meaning" to a theory one would have to apply the theory to some situation (the theory "models" a certain empiric situation). In this sense you know the meaning of something (a thought, a feeling etc.) if you know what it refers to. Conversely, in order to understand how the facts "hang together" and to get their "significance" one needs a theory to describe the relations between them. In this sense you known the meaning of some facts if you can integrate them into a theory. (The quotes in this paragraph are called scare-quotes.)
Another example is the distinction between "words" and "meanings". Words are material things (sounds in air, ink on a paper, light on a screen) while meanings are spiritual things (you need a mind to hold them). By doing mechanical things to words, combining them according to some "formal rules" (i.e. what syntax does), you cannot get to their meaning (to semantics). But how do we get from words (or sentences, or discourses) to their meanings?
Softening the facts and informalizing the theories
If one studies the actual scientific theories, one quickly discovers that the distinction between the "hard facts" and "formal theories" is a myth. At any point one has both a theory and some observations mixed together. As Nietzsche famously said, "there are no facts, only interpretations of facts". The complete statement should be "there are neither facts nor theories, only interpretations of facts (or models)".
Even the simplest observation, such as seeing something, is made in conjunction with some theoretical assumptions, such as the assumption that light travels in straight lines. Illusions such as the bending of a stick in water reveal this. (More about such matters in: What Can We Learn from Optical Illusions?) And even the apparently most formal theories or entities, such as numbers or topology, are understood on the basis of practical experience (more on this in Where Do Numbers Come From?).
We use words to do things
Words and sentences, either uttered or written, are not just understood by the listener or reader - they have an actual impact. Words and sentences have effects upon others, they change their behavior.
I can tell you that a proton is made of quarks. Does that really mean anything to you? Or does it mean the same thing to you as it means to Stephen Hawking? The sentence "the proton is made of quarks" gained a certain meaning for Hawking because he learned to do certain things with this sentence - the sentence has a great deal of consequences for him. In other words, this sentence influences his behavior.
Thus, the distinction between the meaning of the words and what the individual does with the words is also overrated. These are not independent variables, they are also impossible to disentangle, in the same way as the theory and the facts cannot be separated. If you want to know what something means for somebody, you have to look at the actual consequences of that sentence (or discourse) for that person.
Exorcizing the homunculus?
These clues from the philosophy of science or of language can be used as guides when dealing with the mind / body problem. The point should be that both the mind and the body are idealizations. They are useful for describing various things (e.g. perception, thinking etc.) but nonetheless they have their limitations and one should not take them extremely serious. For example when one starts to think about the spirit as being immortal and capable of having an existence outside the body, one definitely has gone too far! The lesson from the philosophy of science and of language should be that in some sense what exists is only the combination or mind and body. But how could that be?
The solution to this problem, or at least the best solution up to date, has been given by Daniel Dennett and it is so smart that at first it definitely sounds crazy. The solution is not to kill the homunculus but instead to give him structure: to separate it into a system of dumber and dumber homunculi. At each point, each homunculus has both a body and a spirit (in other words, it is both material and a holder of some information). One thus has this hierarchic system of increasingly dumber homunculi until we reach the fundamental level (the lowest level) where the homunculi are so dumb that they can only ask one single yes-or-no question over and over again. These fundamentally dumb homunculi are none others than the neurons.
The neuron is a cell and thus a highly complex living organism. But its function in the human body is very simple. Each neuron gathers with its dendrites signals from other neurons and if the sum of all these signals is above a certain threshold the neuron fires through its axon his own signal to other neurons (if the sum is lower than the threshold it doesn't fire). Each neuron receives signals from many neurons and forwards only one signal. (The effect a neuron has on another neuron is to either inhibit or to amplify the signal. Very few neurons manage to have both inhibitory and excitatory functions.) Thus, what each neuron does in the human body is to ask again and again one single yes-or-no question: "Is my signal here? Is my signal here?" And if the answer is "yes" it fires.
But the meaning of the signal depends on the location of that neuron in the neuronal net. In the same way as the meaning of words depends on the context in which they are used, the information held by neurons depends on the context in which they are firing. There's one thing for the neurons in the visual cortex to fire in correlation to the neurons in the retina (it's called perception) and another thing to fire without the neurons in the retina (it's called hallucination - which can be produced by certain drugs that mimic the neurotransmitters and happen to excite various neurons in the brain).
Meaning functions top-down: The context of your discourse determines how your discourse is understood (e.g. there's one thing to talk about tax cuts when everything seems fine or in the aftermath of Katrina), the meaning of the sentences depends on the general outlook of the discourse (the same sentence can be an insult or an objective observation depending on the context), and the meanings the words have depend on the meaning of the sentence (words usually have many possible meanings and we identify their specific meaning based on the contexts in which they are used).
The same is true for the neuronal network. The brain is structured in many regions each having a certain function. In various contexts, for example when you see your mother, areas get activated in conjunction with each other. This is remotely similar to the way sentences are grouped together in a single discourse. In order to form the discourse you have to put together many sentences so in certain sense the discourse is the consequence of the sentences, but the meaning is constructed the other way around. Similarly, when you see your mother various areas of the brain fire in conjunction, areas regarding the visual identification, areas regarding emotions etc., and you identify your mother as a consequence of the fact that all these areas have fired together (if some are damaged you cannot recognize her as it happens to some people who have suffered brain injuries). But the meaning stored by each of these areas in a certain context goes the other way around, top-down: for example the activation of the amygdala (which deals with emotions) has some significance when you see your mother and supposedly an entirely different significance when you see, say, a bear.
Thus, the solution to the mind / body problem is two-fold: On one hand it implies the fact that the basis of all spiritual life is material, the spirit is a feature of this complex structure we have in our skull at it exists only as long as the structure is functioning, and on the other hand the fact that each of these hierarchical material structures involved are not "just" machines doing "formal" stuff, but are also carriers of information. All the way to the dumbest of them all.
As Daniel Dennett put it: "Yes we have a soul, but it's made of tiny robots."
For one of the main objections against this theory see: The First Person Authority Myth
