Inward Larches

We start Charles Darwin's The Descent of Man in the freshman honors seminar next week. First published in 1871, it was Darwin's second big book, and this time he didn't dance around the implications of his theory. It made a lot of people in his day nervous and it will unsettle a few of my students in the weeks ahead as well.

Indeed, Darwin fundamentally changes the debate about human nature. Since at least the time of the Greeks, human beings had taken for granted that they were essentially different from animals, if not in fact partially divine. For Plato and Aristotle we were distinct because of reason, for early Christians because we were formed in the image of God. Darwin collapses the distinction between humans and animals and argues that the difference is one of degree, not kind. Furthermore, he contends that human nature, like the nature of all other forms of life on this planet, is the result of a long process of change in response to natural selection.

Of course it's common to hear people speak of "Darwin's Theory of Evolution," but this is technically a mistake because the idea of evolution was in the scientific air for many decades before Darwin published his works. What Darwin contributed was an explanation for how evolution occurs, not that it occurs. Evolution is merely the idea that species evolve from other species and change over time (descent with modification). The logic that supports this idea is based upon three facts:

First, every living creatures ever observed came from a living parent. No evidence has ever existed that life appears spontaneously. Thus, every living animal, plant or bacterium has come from another living form.

Second, species differ. This point is self-evident. Some have backbones (vertebrates); some do not (invertebrates). Even those people who chose not to believe in evolution agree that species differ.

Third, every piece of evidence ever collected agrees that relatively simple animal and plant species existed before more complex ones. The entire fossil record consistently shows that invertebrates preceded vertebrates. Keep in mind that all that has to happen to disprove the theory of evolution is for a single older vertebrate fossil to appear, but one never has.
When you put these three facts together, you can only reach one conclusion. Life forms on earth today evolved from ancestors that were physically very different. Thus species change over time. So arguing against evolution is a bit like arguing against gravity. You are still free to disbelieve evolution, just as you are free to think that gravity won't pull you down when you jump, but you can't call your belief scientifically sound. It just doesn't account for the facts.
What Darwin contributed to our understanding of evolution was his theory of natural selection. Essentially, he argued that species change in response to their environment. They are, in fact, constantly struggling against the environment and one another in order to survive. This struggle eliminates those unable to compete or adapt. Consequently, given enough time, a species will be physically modified as it takes on the hereditary features of those of its members that have successfully survived and reproduced in the prevailing conditions.
It's a simple idea and backed up by a host of observable evidence, yet many people remain troubled by his theory, and not simply because it seems to contradict the creation story in Genesis (by the way, most cultures have a creation story. Even if evolution is wrong, Genesis is not without competition). No, Darwin's ideas and evolution continue to disturb because they suggest that we aren't as special as we once believed. In this sense his work can be seen as a blow to our species' egocentrism.
Moreover, the process of natural selection is essentially random. There is no overarching goal we're heading toward, just continual adaptation or extinction. This means that who and what we are as a species is contingent upon random chance, a not altogether heartening notion. Lastly, some of the implications of Darwin's theory lead us to the view that to a significant degree our biology controls our destiny, which means our will is not ultimately free.
On the other hand, some people are enormously excited by Darwin's revolutionary view of humanity and nature. They take comfort in the idea that all life is intimately connected and interdependent. For them, it is a perspective as awe-inspiring as any creation story, a view filled with wonderment and surprise. Darwin himself expressed this sentiment in the final lines of his first great work, The Origin of the Species:
There is a grandeur in this view of life, with its several powers having been originally breathed into a few forms or into one; and that whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful have been, and are being, evolved.


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