The Great Conversation: Evolution
By Gabriel Blanchard
The development of life, from the bacterium to the bass player, is a largely modern contribution to the Great Conversation.
Evolution is one of the more contentious terms to appear in Adler’s Syntopicon. Charles Darwin published On the Origin of Species in 1859, setting forth his theory of natural selection as the mechanism of the development of all life, including human life. Debates over its scientific merits and philosophical significance have raged ever since.
Of course, the theory has (forgive the pun) evolved in that time. For that matter, it is not a completely new idea. Selective breeding is probably as old as having domesticated animals; Empedocles, a disciple of Pythagoras, claimed that life first emerged in the form of random body parts, whose random combinations eventually produced life as we know it. Jean-Baptiste Lamarck, an eminent biologist of a generation before Darwin’s, also set forth a theory of the evolution of life. However, Lamarck’s work had certain shortcomings, and the younger scientist stepped past them with his theory.
Darwin’s concept of natural selection is not complex. In a given environment, creatures with traits that work well in that environment—say, birds whose coloring blends in with their surroundings so that predators cannot find them—are likely to survive and reproduce, passing on these helpful traits. Creatures that lack these traits are less likely to survive, and therefore less likely to pass on their unhelpful traits. Hence, the traits of the population as a whole will slowly change over time. Later authors have also referred to this process as microevolution, or evolution within a species.
In itself, natural selection is not controversial. But Darwin advanced the theory that all life, including human life, was produced by natural selection. The idea of a species evolving into one or more different species, or macroevolution, did spark controversy. Many scientists and religious leaders felt that this would eliminate the need for a Creator and the special status of man among the animals. Whether they embraced or disputed Darwin’s work often reflected whether they thought that dispensing with God and God’s image was good or bad. But the controversy was not simple; some Christians accepted the theory of evolution, arguing that an omnipotent God could create just as easily via such a process as in any other way. The Austrian monk Gregor Mendel made important advances on Darwin’s theories, correctly identifying the mechanism of heredity that we now call genes.
The introduction of new traits remained a problem, however: no amount of selection among existing traits could, by itself, produce new ones. Mutation, however, could. Nineteenth century conjectures about mutation trended toward the cartoonish; some scientists believed it could produce immediate leaps from one species to another—the first chicken hatching from a lizard’s egg, as it were. Later thinkers were more conservative, grounding their theories in observable mutations and their effects. The consensus among modern biologists is that, over millions and even billions of years, mutation produces the variety which natural selection winnows.
Another puzzle for modern scientists is how life itself began. If life arose from mere matter, how did it cross that threshold? One hypothesis is that of the “RNA world.” Like DNA, RNA can store and transmit information; but its simpler structure makes it a possible link between the more complex DNA of life as we know it, and the simpler nucleic acids that compose DNA. Some viruses use RNA instead of DNA to maintain themselves: viruses may have been a stepping-stone between inanimate matter and bacteria, or they may be decayed relics that were once alive.
Turning to its role in culture, there is more to evolution than its place in the “war between science and religion.” Some eminent psychologists, notably Carl Jung, proposed evolutionary causes for aspects of the human mind, and neuroscience continues to illuminate our grasp of matters like perception and memory. Evolution is also widely viewed as the basis for, or a backdrop to, progressivism—the idea that humanity and civilization naturally improve over time. But, despite the harmony of atmosphere between evolution and the idea of progress in culture and politics, progressivism did not spring from evolutionary theory. The roots of progressivism lie in the Enlightenment; Fichte, Hegel, Marx, and other thinkers constructed whole philosophies of history on the basis of progress. Romantics like Percy Bysshe Shelley, taking up the ideals of the French Revolution, helped make progressivism popular long before Darwin ever set pen to paper. And progressivism itself displays variety—and mutation. Some of its facets, like Abolitionism, have triumphed, while others, such as eugenics, have (mercifully) gone out of fashion. If there is any real, metaphysical similarity between the tree of life and the wheel of fortune, we do not seem to have uncovered it yet.
Aristotle, History of Animals
Georg Wilhelm Friedrich Hegel, The Phenomenology of Spirit
Fr. Gregor Mendel, Experiments on the Hybridization of Plants
Julian Huxley, Evolution: The Modern Synthesis
C. S. Lewis, The Problem of Pain
Stephen Jay Gould, Hen’s Teeth and Horses’ Toes
If you enjoyed this post, you might also like Alec Bianco’s piece on why we use controversial authors on the CLT, our previous Great Conversation post on the history and philosophy of science, or Mila Patrick’s essay on the black hole information paradox.