- Title:
- Descartes' Error
- Subtitle:
- Emotion, Reason, and the Human Brain
- Author:
- Publisher:
- HarperCollins Publishers Inc., 1994
- ISBN
- 0-380-72647-5
Descartes was a French philosopher and mathematician who is credited particularly with the phrase, "Cogito ergo sum" - "I think, therefore I am." It was the essential basis for a treatise on how we know what's real and what's an illusion. To be sure, Descartes wasn't the first to use the phrase - credit should probably go to Plato, though he said it in Greek instead of Latin. And Descartes wasn't the first to consider the phenomenon of consciousness. But his version is what we remember.
The error that the book refers to is this: he asked the question, "Who is doing the thinking?" He concluded that there must be a soul, a second entity that looks out of our eyes and observes what we experience, akin to the pilot of an aircraft, or better, the pilot of one of those gigantic battle robots from Japanese animation. The error was based on the observation that the mind was capable of rational thought as well as being swayed by overwhelming emotion. The one was ascribed to the soul, the other to the animal nature of the body.
Of course the trouble with the soul is that, besides the subjective experience of looking out of our eyes, there is nothing to show that such a thing exists. It can't be seen. It can't be weighed. More troubling, it appears to be distressingly vulnerable to damage to the vessel which it inhabits.
Damasio starts with a fairly well known example of such a damaged vessel. Most people my age are familiar with Phineas Gage, if not by his name, then by the peculiar injury that he sustained, and which landed him in Ripley's Believe It Or Not. In a freak accident, an explosion drove a rather substantial spike through his skull. It entered below his left cheek and exited through the top of his skull. What made it a freak accident is that he survived it, apparently intact.
But Gage was not the same. His life generally fell apart after the accident. Damasio illustrates with modern clinical examples how specific damage to the brain can cause very similar changes in behavior. These patients might be completely normal in all respects. They know what is going on. They know what choices they have. They know what they should do. They know what would happen if they didn't do it. The one difference between them and normal people is that they don't do it.
You might quote Jesus from the Bible, who exhorted his disciples that the spirit is willing, but the body is weak. But that would mean misunderstanding Damasio. Damasio argues that the willing spirit is an illusion. Our will to act comes from the body, by emotions that it generates in response to signals from the brain. In patients with damage to their ventromedial frontal cortices the body can no longer properly get back to the brain.
Damasio then uses this connection to present a line of reasoning that there is no need for a soul that looks out through our eyes. We are a synthesis of brain and body interacting, producing a continuous stream of mind images of the past and options for the future. Our awareness of this stream is our consciousness.
The argument is not a popular one. That's for two reasons. The one is fairly obvious to most people, especially those living in what's conventionally described as the Western Hemisphere. In spite of living in the twenty-first century, we still have a very strong attachment to conventional notions that are thousands of years old, notions like the soul, which is supposed to be an immortal part of ourselves, something that will survive our deaths.
The other is what's perceived as reductionist materialism, otherwise known as describing everything as physics. This derogatory complaint was particularly common in intellectual circles in the eighties and nineties.
I think it's for these two reasons that Damasio encumbers his otherwise excellent book with more than a dozen pages of apologia, a postscript where he labors to make the brilliant deductive reasoning of the preceding 250+ pages "relevant." Which is kind of ironic. When he finally gets around to explaining what Descartes' error was, he points out a few passages that make it less than clear that Descartes in fact was a dualist, i.e. someone who believed in a soul separate from the body. In a similar manner, these last dozen or so pages add nothing to the book except to muddy the waters.
But this cosmetic complaint is all I have about the book. Damasio doesn't talk down to the reader. He doesn't hide behind handwaving. He even points out where his reasoning is based on supposition, and where the facts are in dispute. The book struck me as an eminently honest discussion. Damasio is easy to read, in spite of the fact that he peppers his prose with neurological terminology for parts of the brain. In short, it's a great book. I recommend it.