Darwin, The Prequel

Charles Darwin's family was a well-to-do family of doctors—his mother was a Wedgewood (daughter of the Wedgewood); his father and grandfather were both doctors—and it had always been assumed that Charles (1809–1882) would be a doctor too. Unfortunately, surgery made him queasy, he hated medicine, and he was nearly flunking out. He was always fascinated by nature. The family gave up on him, and sent him to divinity school to become an Anglican minister and naturalist instead. He didn't like the ministry much, and got a job on a ship as ship's naturalist, on H.M.S Beagle.

Why was a minister suitable to be a ship's naturalist?

Darwin was a Victorian-era (1837–1901) minister, and everyone in the Victorian era was fascinated by, and knew a lot about science. That was the period in which the world was transformed by technology, including the steamship, the railway, buses, subways, commuters, the telegraph, the telephone, the trans-Atlantic cable, the electric light, the phonograph, and movies—until the Victorian era, the technological circumstances of daily life hadn't changed much since the time of the Romans. As a result, it was also a period of popular science books and lots of college science courses.

That explains why a minister might also be a scientist, but why a naturalist, someone who studies plants and animals as they function in Nature? To explain that, I need to say something about scientific naturalism.

Aside on scientific naturalism

Scientific naturalism, is the idea that the structure, processes. and origin of the world can be explained by science, without the need to postulate intervention by anything external to the world or inexplicable by scientific means, for example, a Creator.

Some warnings:

At one time, it was an "obvious" empirical fact that there was a Creator:

The Heavens revolved around Earth, which was the center of the universe. The whole thing was explained, as it had been since Aristotle, in terms of tendencies, goals, purposes, and functions, and its function was to house people. It was thought to be kept in motion by a "Prime Mover," who was also, by late medieval times, the Creator.

In the 1490s, a new continent was "discovered" by Europeans. If the Christian God had created the world, how could He have created people on a disconnected continent without access to the teaching of Jesus?

The Earth was moved from the center of the universe by Copernicus, who delayed publication until his deathbed, in 1530.

In 1612, Galileo proposed a law of inertia, which explained how things could keep moving without a Prime Mover to push them.

Newton's theory (1687) suggested the possibility of other inhabited worlds. That made the problem of access to the teachings of Jesus even more acute.

In 1796, Laplace, building on a suggestion of Kant, showed how the solar system could have been formed in accordance with Newton's laws—Newton had just assumed God put the planets where they were.

By Darwin's time, there seemed to be a more-or-less complete explanation of the cosmos in accord with scientific naturalism. The only place left where scientific naturalism failed—that is, where there seemed to be scientific evidence for the existence of a Creator—was in the study of living Nature. As we discuss below, the prevailing theory was intelligent design. Thus, it was an obvious choice for a minister interested in science to become a naturalist. It wasn't just Darwin. The country parson who was an amateur naturalist is a cliché of Victorian literature.

Back to the origin of evolution

The prevailing theory was that of separate creation (of species). God created each species, and the species are as they have always been, fixed and unchanging creations of God. Thomas Jefferson discovered some mastodon skeletons (ancient precursors of elephants). His chief problem in explaining them was that they can't be extinct— God would never allow any of his creations to be so imperfect as to be subject to extinction. That wasn't just Jefferson's view, it was the ordinary view of the day.

Evolution was just the idea that species weren't fixed. It could be something as minimal as the idea that certain species (domesticated animals, for example) changed over time.

French enlightenment philosophers (Diderot, Maupertuis, Montesquieu, ...), just before 1800, had in many ways begun to question whether the Bible should be taken literally and used as a source of information for science. The part of the story that concerns us is that about the origin of species. The Biblical dogma (an adaptation of Aristotle's idea that species are eternal) is that God created all the species in their infinite perfection about 6000 years ago (on a Thursday). Many French enlightenment philosophers believed that species can transform, for the same reasons we do now: breeding of varieties, sports, monsters, similarities between species, vestigial organs, embryology. Diderot even suggested that there was a single life form from which all others were descended. Erasmus Darwin (Charles's grandfather) published similar views a bit later.

How did it happen that French Enlightenment philosophers started trying to understand the world without the help of the Bible? There seems to have been a general cultural shift away from religion, that they followed.

Lamarck had a theory of transformation (1809) similar to those of the people mentioned above. He usually gets the credit (or the blame). but he was also an important advocate of uniformitarianism, a view that seems to originate with Hutton (1785). Lamarck (1802) clearly explained the origin of sedimentary rocks, and he showed that one can organize living and fossil organisms into plausible trees of transformation.

The Biblical dogma made the world only 6000 years old. However, many of the earth's geological formations have been created since then. 6000 years is not much time to dig a ditch the size of the Grand Canyon, and so the standard view of geologists was what is now known as catastrophism: there were huge events that made many features of the earth in a matter of days. There were Noachian floods, volcanoes of unimaginable size, ... .

Hutton and Lamarck advocated uniformitarianism in geology—the view that what came before is just like what is going on now, and that the Grand Canyon (for example) is still being carved, it is just happening really s l o w l y. That gave reason to suspect that the earth is really old (Lord Kelvin story, which worried Darwin enough to play a role in his weakening his theory of natural selection in later editions of the Origin of Species by relying more on the "Lamarckian" idea of the inheritance of acquired characteristics) and employed a general principle of explanation, a general scientific attitude, that is also important to Darwinian evolution: the principle that one should assume that the same processes that act today acted in the past, that it is a bad idea to postulate occurrences of a sort never observed, at least not without strong evidence. (Alvarez story).

Before getting to Charles Darwin, let's look at earlier evolutionary theories.

By the 1820s everyone and her sister had a theory of the transformation of species, including those mentioned above. All of these theories have one thing in common that is worth emphasizing, because it is the problem with the theories that

None of them had a good mechanism for how fruitful changes took place. They all used some stew of an assumption that the ways organisms devised to live their lives got inherited (now often called Lamarckianism) with some principle of organization that led to new organs and structural complexity—a principle of the Aristotelian sort involving goals and purposes.

Since such theories postulated a march of progress for every organism, one had to explain why there were still primitive organisms like one-celled creatures around. Spontaneous generation was a standard way of doing that, and so spontaneous generation was associated with evolution, for example, by the judges of the Pasteur-Pouchet competitions around 1860.

Several elements gave Darwin hints he needed:

Cuvier was a catastrophist geologist who saw mass extinctions in the fossil record followed by replacement by completely different organisms (1812). He was the first to recognize the possibility of mass extinctions. Species may or not be modified over time, but they die out, a possibility Cuvier's predecessors had rejected. He was also the founder of methods of careful examination of fossils and the comparison of them to living species. He proposed that animals divided into four major groups (representatives of the groups include jellyfish, insects, snails, fish), and was the first to emphasize the principle of correlation: the importance of small variations in the shapes of bones. (Mention how to distinguish reptiles from dinosaurs.)

Lyell, Cuvier's opponent, was an eminent uniformitarian (1830) who emphasized just how old the earth had to be. His work was largely responsible for the final victory of uniformitarianism over catastrophism. He opposed evolution because of the lack of intermediate forms in the fossil record. He accepted extinction and the origination of new species.

Richard Owen coined the word "dinosaur" in 1841. They were still only known to a small circle of specialists.

That sets the general background. The next two works deserve to be distinguished, because they played a particularly direct role in Darwin's thought. Ironically, both were attempts to give arguments for the existence of a Creator.

Malthus (1798). The normal rate of population growth of any living thing is geometric (chessboard story), while that of its food supply is arithmetic. Thus, starvation and want are the normal situation of living things, including people. He used that to argue that human misery is inevitable and to argue against the Enlightenment and Victorian values of trying to improve the human condition. It is impossible, and we must rely on God for solace. His view was the antithesis of the romanticized Victorian view of the beauty of nature. "Nature is red in tooth and claw" (Tennyson, "In Memoriam," 1850; applied by Huxley to evolution).

Paley (1802), an adherent of Malthus. His work was the standard reference for the standard theory during Darwin's college years, a theory some are trying to revive today: Intelligent Design. Seeing a rock on the heath tells us little. For all we know, it has been there forever. What if you see a watch? Someone has been here before.

Why is the watch different from the rock? Unlike the rock, the watch is clearly designed for a specific function. It has many parts that work together in an elaborate manner. We can discover elaborate reasons for why many parts of the watch must be as they are to work together, but nothing like that is true of the rock. The only way, Paley says, that there could be a thing like a watch, a thing with a clear functional role, is if it had a designer. Even if the watch could make other watches, so that it might have been made, not by a designer but by another watch, there must have been a designer to set the process going in the first place (42–43): A watch that makes another watch does so because it is so contrived as to do so. But there must have been a Watchmaker, an artificer, in a different, final sense—one who gave the various parts their functions, their intended use. Such explanations in terms of functions and goals are incompatible with scientific naturalism.

The self-reproducing watch, obviously, is a metaphor for life. To complete his argument that life must have had a designer, he needs to show that living things have parts with clear functional roles, like the parts of the watch. In what we read, he uses the eye as an example. Paley was part of a, very English, tradition of taking the marvels of nature to be a proof of the existence of God. He explained misery and death (which are a problem for the theory) using ideas of Malthus. He discussed many examples besides the eye, providing a valuable list of test cases for Darwin.

A note on dates: Dates I have given are, for the most part, dates of important publications on the subjects being discussed. They are often, but not always, dates of the most widely cited publications, which suggests dates at which views became influential. They are sometimes, but not always, dates of first publication of an idea by the author, and I make no claims that the authors to whom I attribute ideas are always the originators of those ideas. I am attempting to trace influences on Darwin, not who deserves credit.

-- ShaughanLavine - 27 Nov 2005 - 28 Nov 2007