Voltaire: A Homily on Scientific Certainty

In one of Voltaire’s tales he describes an incident in which the hero, Zadig, is injured in the eye by a band of ruffians. When an infected abscess develops, a great doctor is sent for to treat the wound.

A messenger was sent as far as Memphis for Hermes, the famous physician, who came with a numerous train. He visited the sick man, and declared that he would lose the eye; he even foretold the day and the hour when this unfortunate event would happen.

“If it had been the right eye,” he said, “I might have cured it, but injuries to the left eye are incurable.”

All Babylon, while bewailing Zadig’s fate, admired the profound scientific research of Hermes. Two days afterwards, the abscess broke of itself, and Zadig was completely cured. Hermes wrote a book, in which he proved to him that he ought not to have been cured, but Zadig did not read it.

Voltaire’s story might as well have been written to skewer the behavioral scientists of the 20th century as the medical doctors of the 18th. Their fine theories, too, ended up in a train wreck with reality. That reality is manifesting itself ever more clearly, as remarkable new discoveries seem to be coming in on an almost daily basis. Those discoveries are demolishing absurd certainties about human behavior in our own day as thoroughly as the wonderful geological discoveries in the middle of the 19th century demolished only marginally more absurd Biblical certainties about the age of the earth.

Among the more interesting results of recent research has been the tracing of specific behavioral traits to the subtle variations in genes that are most important in their expression. For example, a paper that appeared in the journal Psychological Science describes a statistical method of associating changes in single letters of DNA chains, known as single-nucleotide polymorphisms, or SNPs, with differences in sensation seeking behavior. As noted in a review of the paper in Science News, these “new methods are letting scientists look for more subtle associations between genes and all kinds of traits, including behavior and personality.”

In the book Endless Forms Most Beautiful, Sean Carroll describes recent developments in the emerging field of evolutionary developmental biology, or “Evo Devo.” We are finding surprising similarities in the genes responsible for assembling complex features of our own bodies as we develop from a single fertilized egg with the analogs of those features in animals with which we have not shared a common ancestor for hundreds of millions of years. It would be very interesting to apply these new technologies to see if we share genes for the expression of related behavioral traits that go back a very long way as well.

Many are still as fondly certain that our morality sharply distinguishes us from other animals as others before us were certain that we are the only animal capable of making and using tools. I suspect we will find that, on the contrary, many of the fundamental building blocks of our morality have also been around for many millions of years. It may well be that the seemingly unique complexity of our moral behavior does not result from any fundamental disconnect between the innate mental traits responsible for its expression in ourselves and other animals, but merely from the fact that those traits are mediated by our greatly superior intelligence.

Author: Helian

I am Doug Drake, and I live in Maryland, not far from Washington, DC. I am a graduate of West Point, and I hold a Ph.D. in nuclear engineering from the University of Wisconsin. My blog reflects my enduring fascination with human nature and human morality.

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