Tuesday, November 27, 2012

On Darwin's Bad Days And Long Ponderings

On Krulwich Wonders, Robert Krulwich mines Darwin's correspondence with Charles Lyell in which he complains of bad days and feeling poor and stupid. The great man was not worrying about natural selection but rather an upcoming book on orchids!

There is more on Darwin's tendency to be anxious and careful about his ideas and data:

In his short biography of Darwin, David Quammen writes that he was "nerdy, systematic, prone to anxiety." He was not quick, witty, or social. He spent decades working out his ideas, slowly, mostly by himself, writing letters and tending to a weak heart and a constantly upset stomach. He was a Slow Processor, who soaked in the data, thought, stared, tried to make sense of what he was seeing, hoping for a breakthrough. All around were snappier brains, busy being dazzling, but not Darwin's, which just plodded on until it finally saw something special, hiding in plain view.

Plodded on until it finally saw something special, hiding in plain view.

To that I will add that most people can't see something special, hiding in plain view. Inspiration often comes to the prepared mind and Darwin through his meticulous observations and prolonged days of thinking had a prepared mind, one that was not ideologically constrained but one that could accommodate and not summarily reject more radical notions of nature and change.
I am reading right now from  Darwin's Timeline which summarizes chronologically his life. There is a section on his life and work in London after he returned from his epic voyage on the Beagle in 1836. In it are two incidents which sowed the germs of two of the most important ideas on the nature of life and evolution; common descent and natural selection.

The first was in the months of 1837 when ornithologist John Gould on examining the collection of birds from Galapagos announced that what were cursorily identified as finches, wrens and blackbirds were all actually closely related varieties of finches. Why the confusion? Because the birds all had distinctly different shaped beaks. The prevailing world view of nature was that organisms could be grouped into different "kinds" distinguished by large differences in some trait or a collection of traits. Taxonomy was a flourishing field then and that species could be organized into hierarchically related groups was well understood. But that was seen to be the Creator's way of ordering the natural world.

Darwin on receiving Gould's interpretation that these birds were really closely related varieties of just one "kind" i.e. a finch began thinking on a different interpretation of the tree of life, on ways by which one species may change or transmutate into several species differing in one character, in this case the beak. His own collection of finches from the Galapagos was a mess. He had not labelled the birds by the island he collected them from. Fortunately, some other sailors on the Beagle had and using their collection Darwin could place the variation of beaks in a geographic and ecologic context. Perhaps few finches made their way from the South American mainland and populated different Galapagos islands? Isolated on different islands,  some force may have led to the differentiation of beak shape, each specific to a particular island ecology. That is common descent and adaptive radiation as we understand it today. More than natural selection, common descent is probably Darwin's most original contribution to biology.

The second "moment" for Darwin came in October 1838 when he read Thomas Malthus's essay on human population growth. Malthus argued that human populations grow until there is a resource scarcity, thereafter which a struggle for existence ensues and the weak die off. Darwin recognized that resources are limited in nature and a struggle for existence must be taking place wherein some organisms survive to reproduce while those not possessed with the right characters die out without reproducing. Populations will gradually change in character as generation after generation passes through this nature's filter, a process he called natural selection.

The Darwin Timeline is fascinating to read.  In all those months of thinking and rethinking there would have been bad days and days of frustration as Robert Krulwich points to. But Darwin was truly great not just because he had a couple of great ideas but because he took a firm grip on them and had the intellectual courage not to let go even as he increasingly realized that his theory would demolish cherished notions of our place in the universe.

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