The mind-body connection

“For many, consideration of the human mind takes us beyond the realm of the physical and involves metaphysical (i.e. beyond the physical) philosophising.” Alan Watts

Numerous people believe that there is a separation between body and mind: that they consist of two different kinds of stuff. You have only to visit your local bookstore and browse its catalogue to find proof of this common conviction: copious volumes devoted to improving Mind and Body or, more usually, Mind, Body and Spirit. Indeed, the mind is often equated with notions of a soul or the essential ‘I’. For some this sensation of an ‘I’ is construed as the real, autonomous being that I am. It is sometimes felt as being apart from my body, making voluntary decisions as I journey through life. For others, especially in the West, the ‘I’ is perceived as being intimately associated with the body, being located in the head somewhere behind the eyes. But this may not be a universal perception.

Consider the Chinese character xin (Figure 1) which can stand for both mind and heart. It is, however, typically translated as the composite mind-heart. This may be indicative of an oriental view of mental activities being conducted in the heart rather than in the head.

Figure 1. Xin (mind-heart)

The philosopher Alan Watts has commented upon the specific sensations for which people use the word ‘I’. He notes that few people seem to use the word for their whole physical organism: ‘I have a body’ is more common than ‘I am a body.’ We tend to speak of ‘my’ legs in the same way that we talk about ‘my’ clothes – but ‘I’ remain intact even if my legs are amputated. We say, ‘I speak, I walk, I breathe’ but not usually ‘I shape my bones, I grow my nails’ or ‘I circulate my blood.’ But whatever the situation, Watts concurs with the view that people frequently use ‘I’ to refer to some centre of voluntary behavior. For many, it is also what we perceive as our centre of consciousness.

Modern view of the mind

It is another philosopher, René Descartes [1596-1650 CE], who is best remembered for the proposal that matter (body) and mind are composed of two different kinds of stuff: material substance and mental substance. For modern science, however, this position is no longer tenable. There are many reasons for this but three examples will serve our current purpose.

Everything’s made of the same stuff

First, modern physics has shown that the whole cosmos is constructed of the same material and that everything arises from a universal energy field. This arising takes place in the so-called quantum world: a strange, counterintuitive level of reality where the fundamental particles that make up the atoms of our universe pop unpredictably in and out of existence. This understanding, that energy and matter are one and the same, is embodied in Einstein’s most famous equation, E = mc². Thus, physics shows us that the electrons that orbit the nucleus of a hydrogen atom, for example, are exactly the same in form and behavior as those that orbit any other atom – of magnesium, carbon, or whatever. Consequently, if you were suddenly to swap all the electrons in your brain with electrons gathered from a distant star you would never know the difference. You would continue to perform your mental operations with the same lucidity as before. Everything within the universe is composed of the same stuff. In other words, according to modern physics, there is nothing beyond the realm of the physical.

Brain biochemistry

Second, it is now easy to demonstrate that by altering the biochemistry of the brain with, for example, psychoactive drugs one can readily alter a person’s mental perceptions. It is precisely this effect that is exploited by the prescription of drugs such as amitryptiline and fluoxetine (prozac) that function as antidepressants. They are capable of affecting a person’s mental state – hopefully for the better.

Neuroimaging

Third, the use of modern neuroimaging techniques such as positron emission tomography (PET) scans demonstrates that particular regions of the brain use differing amounts of oxygen and glucose when a person is engaged in mental activities, such as solving a crossword puzzle or performing a mathematical calculation. In sum, these last two examples demonstrate an essential link between brain processes and mental processes, i.e. mental processes are dependent upon an intact, properly functioning, physical brain.

The mind is what the brain does

The emerging consensus (under the general rubric of ‘radical materialism), then, is that the mind is what the brain does. And what does the brain do? It computes – it processes information and, it is claimed, thinking is merely one kind of computation. Admittedly, it appears to be a different kind of computation to the seemingly straightforward computer calculations that rapidly determine that one plus one equals two but, nevertheless, it is still a form of computation. If the mind is not the brain but what the brain does, we need to be clear that it is not everything that the brain does. For example, in common with other organs in the body, its cells respire, converting glucose into energy. Also, different parts of the brain regulate and control other functions. The brain stem, for example, is responsible for automatic regulation of vital functions such as breathing, heartbeat and blood pressure; the cerebellum is associated with the co-ordination of movement, posture and balance. Such regulatory functions are not generally considered to be part of the human mind.

Just like a computer?

One should also be wary about assuming that because the brain performs computations that it is, therefore, directly analogous to a computer. There are many differences between our current computers and brains. For example, computers perform serial computations but brains compute in parallel. That is to say, computers perform one computation after another in a series whereas brains perform many millions of calculations all at the same time. For some researchers (Dennett, 2010), however, this is not so much a declaration of an absolute difference between computers and brains but more a statement about our current technology, i.e. the human brain is just more advanced than today’s computers. If we accept that the mind and consciousness are merely the product of computations then, according to some, any claim that consciousness is what makes humans superior to machines is unfounded.

Clearly, the brief accounts provided here regarding the mind-brain’s functioning are gross oversimplifications. But they serve to demonstrate some of the current thinking about the human mind. And, indeed, it is this very act – thinking – that we humans typically claim sets us apart from (other) animals. Uniquely, it seems, not only are we capable of thinking but we can think about thinking. We know, and we know that we know. We are conscious of being conscious. This faculty of mind undeniably sets us apart and affords us many advantages. Exclusively, it seems, humans are capable of predicting the future. [Although there is some evidence to suggest that other primates are capable of predicting the consequences of their behavior and that they may understand enough about the motives of others to be capable of deceit and other forms of manipulation (see Cheney and Seyfarth, 2008).] Because the future has not yet happened, we must imagine what may happen. I don’t suppose for a moment that my dog ponders whether or not it will be colder tomorrow than it was three days ago, on the basis that there are now snow clouds arising in the northern skies. But humans are capable of entertaining such thoughts and acting on reasoned conclusions: ‘I think I’ll pack another sweater for my trip tomorrow because it’ll probably snow.’ We are also capable of speculating about the consequences of our actions, either in the present or in the future. The faculty of mind allows us to ponder our world and our place within it, to imagine and to create, to act with intent or to choose not to act…and much more beside.

References

Cheyney, D.L. and Seyfarth, R.M. (2008) Baboon Metaphysics: The Evolution of a Social Mind Chicago, IL: University of Chicago Press.

Dennett, D.C. (2010) Content and Consciousness London: Routledge.

Sperber, D. (1994) ‘Understanding verbal understanding’ in Khalfa, J. (ed) What is Intelligence? Cambridge: Cambridge University Press.

Watts, A. (1999) The Book on the Taboo against Knowing Who You Are New York: Random House.