Ernst Mayr, the greatest evolutionary theorist of the 20th century, died last February at the age of 100. Andrew Madden, our obituaries editor (yes, we have one) wrote a very nice tribute to his life and work in the July issue of Technology Review.
Mayr was an extraordinarily prolific and influential figure, developing not one but two distinct biological theories. The first was the modern evolutionary synthesis of Darwinism and Mendelian genetics: the synthesis forms the basis of today’s orthodox definition of species. Mayr’s second theory, developed when he had already retired from active teaching at Harvard, was of peripatric speciation, which purports to explain how new species evolve through geographical isolation. This last idea is still controversial because it does not seem applicable to all species - for instance, recent mathematical models suggest that insects can evolve into distinct species by a weird process called sympatric speciation.
Mayr was also very interested in the philosophy of biology, arguing consistently against “reductionism” - that is, the view that evolution acts only on genes rather than upon the entire organism.
This weekend, I was reading through Philosophy of Biology, edited by Michael Ruse, when I came across a strange little essay by Mayr on aliens. I had no idea he was interested in the subject. In “The Probability of Extraterrestrial Life” (originally written in 1985 for another collection titled Extraterrestrials: Science and Alien Intelligence) Mayr took a very similar line to the one I proposed in a recent post.
Most of the essay is a densely structured argument on how wildly improbable life is at all - and, by extenstion, how even more unlikely is intelligence. But at the conclusion of the essay, Mayr is admirably clear:
“Even if there were intelligent extraterrestrial life, and even if it had developed a highly sophisticated technology, the timing of their efforts and those of our engineers would have to overlap to an altogether improbable degree, considering the amounts of astronomical time available. Every aspect of “extraterrestrial intelligence” that we consider confronts us with astronomically low probabilities. If one multiplies them together, one comes out so close to zero, that it is zero for all extents and purposes.”
Exactly what I said.