Friday, 9 October 2015
TROUBLE WITH THE BRAIN
Most of our organs can be treated as repairable machines. Why can’t we treat mental illness by simply fixing the brain?
An article bearing the above subtitle landed in my inbox this morning. Written by an eminent neuroscientist, emeritus professor Joe Herbert, the essay laments the fact that medical science has not been able to achieve anywhere near the success in treating mental disorders that it has in treating, say, heart disease. The heart, he writes, is no longer a mystery. We know so much about how it works that many diseases and malfunctions of the heart that once killed people or ruined lives can be prevented or fixed by modern medical treatments. We can even transplant hearts as a last resort.
Not so with the brain:
Our understanding and treatment of mental disorders is primitive. Why is that? The burden on our society is huge. A quarter of women will have an episode of depression at some stage in their lives (it’s about half that for men). Most will never reach a doctor or be diagnosed. About 40 per cent of those who do won’t respond to the first antidepressant they are prescribed, and about 60 per cent of those won’t respond to the second. About half of schizophrenics will get better or manage to live reasonable lives: the other half will relapse or never recover in the first place. Anorexia nervosa claims the lives of more patients proportionately than any other mental disorder. But mental disorders are only one category – a rather artificial one – of brain disorders. *
The reason for this, says the author, is that the brain is vastly more complex than any other organ in the body. Despite huge advances in the last few decades in our knowledge of brain function, the brain is still a mystery. We cannot yet use our brain science to predict what neural state will lead to a change in mood, a decision, or a thought. That’s why there is still a huge gap between psychology/psychiatry and neuroscience. He holds out hope that one day that gap will be closed, psychiatry will be replaced by neuroscience, and “then the scourge of mental illness, a tragic and crippling burden for individuals and society, might at last begin to be lifted.”
Most people, I suppose, would read this description with an appropriate mixture of concern and hope. It reflects the mainstream view of scientists and philosophers that the problems threatening our ability to lead healthy lives are physical in nature and will gradually be solved by advanced science and technology. Mental disorders are particularly difficult but will eventually yield to better drugs and neural interventions yet to be discovered (much better than electroshock therapy, we hope) . Have we any reason to doubt this hopeful scenario? Along with many psychologists, philosophers, and even some neuroscientists, I believe we do. What if the entire approach is misguided because the problem itself has been badly misunderstood?
One of philosophy’s main tasks is to identify assumptions in any train of thought that may harbor mistakes. A mistake at the beginning, as in a mathematical problem, will yield an erroneous conclusion. In the case of a policy decision, the result can be, not merely a false conclusion, but a real-world disaster. Think of the assumptions behind the U.S.’s decision to invade Iraq in 2003. If Prof. Herbert’s analysis is wrong, the result could be a waste of billions of dollars in a search for pharmaceutical solutions to mental problems that are not amenable to such solutions at all.
In the first paragraph of the essay, Herbert assumes that mental disorders are brain disorders. This is hardly self-evident, but it reflects the mainstream theory of human nature that prevails among philosophers and scientists these days: that a human is just an organism, a product of biological evolution, more complex than any other type, but still basically just a body with a highly complex brain. This philosophy is known as materialism. In the current context, materialism implies that the mind and the brain are the same thing or that mental states are nothing more than brain states. Prof. Herbert understands full well the main problem that ‘bedevils’ a materialist philosophy of human nature.
Psychology is a description of what the brain does: neuroscience aims to describe how the brain works. The mysterious and seemingly unfathomable gap between them bedevils not only psychiatry, but all attempts to understand the meaning of humanity. We are what our brain is, and our wonderful hands allow us to carry out its commands. But if we can’t explain precisely how we decide to make a movement, let alone how we learn to perform it more accurately, how can we even attempt the greatest task of all: explaining how the brain produces consciousness?
How indeed? And if we can’t explain how the brain produces consciousness, then we don’t know how it produces mental disorders like depression, and therefore we don’t know how to cure them.
Let’s look at depression again. We have some ideas about which parts of the brain are responsible for generating emotion, and even some (rather sketchy) information about which parts of the brain might be dysfunctional in depression (assuming this is a single disorder, which it most certainly is not). But until we have precise knowledge about what distinguishes the brain of a depressed person (or a schizophrenic, or an obsessive one, or whatever), we won’t know how to put it right.
Despite this serious difficulty, Herbert holds out hope that materialist science will one day solve the problem. This is the kind of promissory note that we were handed some 15 years ago by the apostles of genetic biology who were certain a whole panoply of diseases would be eliminated in a few years by genetic medicine and genetic engineering. We are still waiting.
And, I contend, we will be waiting till the Second Coming for neuroscience to solve the problem of mental dysfunction as well. Why? Because the problem has been misdefined. Consider Herbert’s own words again: ...“how can we even attempt the greatest task of all: explaining how the brain produces consciousness?” If Herbert had been trained in philosophy as well as in science, he would realize that this formulation is based on the assumption that the brain produces consciousness. Does it? In a future post, I will argue that this assumption is seriously misleading, that it is only partly true, and to make it the whole truth about our lives as conscious beings is to diminish our conception of human nature and to encourage disastrous social policies.
But first, let us understand clearly what this doctrine says. When Herbert, et al., claim that the brain produces consciousness, they don’t mean that consciousness is in any way independent of, outside of, or other than the brain. The brain doesn’t produce a thought like a factory produces computer chips. No, the claim is quite radical: all conscious activities are nothing more than brain activities. They begin and end in the brain. Depression, for example, is a condition that exists entirely in some region of the limbic system. It is a disorder in the way that neurons interact with one another. And so it is with thinking, imagining, sense experience, and so on. They all happen in the brain. They are all just the zipping around of electrochemical impulses in our hugely complex brains. This assumption raises some awkward questions:
· If I imagine my mother’s face, why can’t a neuroscientist see the image in my brain, even with his state of the art scanning machine?
· If sensation occurs in the brain, why do I feel the pain of a sore toe in the toe and not in my head?
· If seeing a bird in a tree takes place in my brain, why do I point away from my head toward the tree?
On the assumption that the brain produces consciousness, questions like these will remain forever baffling. Once the notion is seen for the absurdity that it is, the answers fall into place rather easily, as I will argue in my next post.
* To read the article quoted here, go to http://aeon.co/magazine/psychology/why-cant-we-unite-neuroscience-and-psychiatry/?