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N. 55, November 2004: I, Robot |
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Massimo seeks the mind-body connection.
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No, this column is not about Isaac Asimov’s famous science fiction novels concerning the interaction between robots and humans (and even less about the recent movie by the same title, very loosely based on said novels). Rather, this month’s essay has been inspired by the reading of Antonio Damasio’s Looking for Spinoza, the third in a series of books by this neurobiologist that attempts to unravel the mysteries of consciousness (the other two are Descartes’ Error and The Feeling of What Happens).
One of the most recurring instances of anti-naturalistic prejudice is the refusal to admit that the mind is a result of the activity of the body; no ectoplasm needed, as philosophers of mind put it. Few today would reject the notion that the body itself is very much like a machine. I was reminded of this rather obvious conclusion during a recent trip to the dentist: listening to a mechanical tool working its way through my teeth in order to fix the problem (I was having a root canal operation) it occurred to me that there was little difference between my predicament and a mechanic working on my car. This is a rather novel conception of the human body: before the work of philosopher-scientist René Descartes in the 17th century it would have been inconceivable even for most scientists to think of the body as a machine.
But the mind, still most people say today, is an entirely different matter. After all, Descartes himself stopped short of extending his reductionist analysis to human thought (though it isn’t at all clear whether he did so out of genuine conviction or as an attempt to avoid the fate of his contemporary Galileo). Yet, consider the following instance, reported by Damasio in Looking for Spinoza. A group of neurosurgeons at a hospital in Paris was conducting a farly routine operation on a patient affected by Parkinson’s disease. The idea was that, since the woman wasn’t responding to drug treatment anymore, the medical equipe would go straight into her brain and stimulate via electrodes specific regions of the brain stem. The procedure usually yields stunning results, which completely erase the symptoms of the disease, greatly improving the patient’s quality of life, at least temporarily.
In this particular instance, however, something went wrong. When one of the electrodes was activated, the patient suddenly stopped talking, began looking very sad and started crying uncontrollably, eventually explaining how her life was meaningless and she wished to die. It is important to note that the individual in question had never shown symptoms of depression before the implantation of the electrode. Even more stunningly, the talk of suicide, the crying, and the sad expression all decreased and then disappeared minutes after the electrode was removed by the medical scientists! If this doesn’t sound like a machine being turned on and off at will by a simple electrical stimulation, I don’t know what will convince you.
A crucial reason why Damasio is interested in cases like the one of the French woman affected by Parkinson’s lies in the exact sequence of events and what it tells us about the nature of human thought. Notice that the facial signs of sadness appeared first, followed by the crying, and only significantly later by the articulation of the feeling of emptiness and despair. The same sequence has been found in other experiments and it suggests that feelings are generated by the brain’s thinking about, or perceiving, the body’s emotions. That is, emotions are simpler physical phenomena, while feelings are more complex, second-order, mental events.
Still not convinced that we are very sophisticated biological machines, in both body and mind? Then consider another fascinating example from Damasio’s book. One of his own patients was affected by a bizarre and rather disturbing condition, which provides a stunning insight into the mind-body connection. The man in question suffered occasional episodes during which he would begin to loose the feeling of the lower parts of his body, as if under local anesthesia. The loss of feeling continued gradually upwards throughout the body, until it reached the throat, at which point the man passed out. A similar condition affecting a female patient did not cause her to loose consciousness, despite the frightening experience of no longer feeling her limbs and trunk. Tellingly, this second patient retained a sensation of her internal organs. Damasio suggests the intriguing possibility, based on these and similar cases, that we have a mind only until we have a body sensation of some sort (even highly incomplete, as in the case of the second patient). However, no body immediately means no mind. What more compelling evidence could there be that dualism is dead in its tracks?
Damasio goes further, and in his book he builds a convincing, if circumstantial, case for the radical idea that the mind actually is a monitoring system of the internal and external state of our body. The mind, then, is not a thing, but a process (of the brain, and hence the body) by which certain animals with complex brains keep track of and control what their bodies are doing. We seem to be well on our way to truly explain consciousness as a biological phenomenon. All of this, of course, is no reason to think that we are “just” robots in the demeaning sense of being “mere” machines having no intrinsic value. There is nothing trivial or simple about the working of the human body and mind. Moreover, human life has value for other humans, and scientific evidence of the kind I discussed here is meant to help us understand how we generate, literally, our selves, not to tell us how much we should value those selves from an ethical perspective.
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Massimo’s other ramblings can be found at his Skeptic Web.
Massimo’s books: Denying Evolution: Creationism, Scientism, and the Nature of Science
Tales of the Rational: Skeptical Essays About Nature and Science
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