The Story of Evolution, Spring 2005
First Web Papers
On Serendip

In What Evolution Is, Ernst Mayr describes the development of the theory of evolution as though it were directional: leading inevitably from pre-Darwin ignorance to its ultimate modern form. The various missteps along the way were temporary and inconsequential, mere hiccups. Science is our tool for learning the "real truth" about the world, he says (3, p.5), and I suppose that any process whose ultimate goal is the absolute truth must necessarily be directional. However, just as it is not very useful to describe evolution as a process leading to perfection, it is not useful to describe science as a tool to find truth. If anything its goal should be a deeper understanding of the universe, and as such any "missteps" along the way would not be inconsequential. Every step along the way, every theory and idea would be significant, since each step would increase our understanding in some way.

Viewed in such a way the evolution of scientific ideas shows many similarities to evolution in nature. An emerging idea can be likened to a novel variation within a population: a mutation, or perhaps a new combination of pre-existing variations. Ideas do not emerge into vacuums. They are subject to selective pressures of many forms. An idea must be received well in order to survive: it must make logical sense, and must be able to defend itself if it contradicts existing theories and the climate of the times. The current body of knowledge about the world must agree with it, as well. Ideas are constantly being retested and rethought and altered to better suit new observations and ways of thinking.

This is not a radically different view from Mayr's view, but merely a difference in perspective: a difference in attitude, focusing on the events of the story rather than its final destination. According to such a perspective, every idea, every theory put forward in history has no absolute truth-value, since there is no way to know the absolute truth. Rather, a widely accepted theory is only widely accepted within its own context and time, just as an adaptive feature of an organism may become maladaptive if there is a sudden ice age.

An example of this is the theory of the spontaneous generation of insects, which was widely accepted for centuries. Insects and other lower organisms were thought to be spontaneously generated by rotting meat and other non-living matter. This view was logical within the context of the theory: no satisfactory theories existed about where life came from, apart from calling it a divine miracle. Insect eggs are small, and could not be seen in the rotting meat. Insects seemed small and uncomplicated, and it was conceivable that such a simple organism could be spontaneously generated. The theory of spontaneous generation was old and respected as well, dating back to the ancient Greeks. (1)

Ultimately, though the environment this theory existed in changed. Experiments were done by Redi and then Pasteur which showed that meat does not spontaneously generate life, but rather insects lay their eggs upon it. With convincing evidence opposing the theory it lost its general acceptance.

Also, just as there is a large element of chance in evolution, an idea that works perfectly well may sink into oblivion by pure chance. For example, the work of Gregor Mendel was rediscovered some 35 after it was published (2) but may easily never have been rediscovered at all.

A series of changes in the environment and a state of turmoil can clear the way for a tremendous amount of new creative thought, just as mass extinctions are followed by explosions of new life and innovations. Conditions were such at the beginning of the 19th century. The French and American Revolutions had just occurred, and continuing industrialization and the rise of the industrial working class were causing turmoil as well. Europeans were exploring the world and discovering the sheer impossible variety that existed in nature. And although this variety itself did not create any problems with the existing worldview, the patterns exhibited by it did. (2)

Darwin's theory of evolution was not so much a response to radically new observations as an alternative explanation of knowledge that had existed for some time. A broad parallel to such a discovery in nature might be the use of a pre-existing organ for a new function. For instance, after lobe-finned fishes began to use their fins for support in shallow rivers, the gradual strengthening of their fins over generations ultimately led to the move to land and an opening of infinite new possibilities.

Darwin saw differences between organisms that occupied similar environmental niches, and similarities between organisms that occupied adjacent but different niches. Under the existing theory of special creation, all organisms were made perfectly adapted to fit their respective niches and such patterns of variation made no sense. (2) Cuvier, a firm believer in special creation, had explained away the similarities between organisms by saying that "God [...] showed his skill by varying the details while retaining the essentials." (1, p.40) Darwin's theory however was that different species have common ancestors which diverged at different points in the past. It fit the known facts far better than any other theory did, and was thus eventually widely accepted.

The potential for this theory had existed for some time. The potential for an idea may exist in society, in social turmoil and broadening knowledge, so that it may be "discovered" several times. An example for this in nature is the eye, variations on which have developed independently 40 times because the potential for its development already existed in the basic genotypes of many species. (3, p. 205) Similarly, the idea that species are not immutable occurred several times in the late 18th and the 19th century. Buffon showed signs of believing that new species arose from old ones later in his life. (1, p.45) Lamarck theorized in the early 19th century both that species were able to change over time and that this occurred because of natural laws, and not intervention by God. In 1831, Patrick Matthews added in an appendix to On Naval Timber and Arboriculture his belief that population growth is kept in check because individuals that "possess not the requisite strength" die before reproducing, and are replaced by "the more perfect of their own kind". (1, p.47) In 1844, a highly controversial book Vestiges of the Natural History of Creation was published anonymously by the Scotsman Robert Chambers, claiming that "everything in nature is progressing to a higher state". (2, p.24 and 1, p.47) And finally, Alfred Russel Wallace and Charles Darwin both independently came up with the theory of evolution in the 19th century, and brought about its ultimate general acceptance.

The theory of evolution continues to be in competition with the theory of special creation, in attempting to explain the history of life on earth. However, in my opinion it does not need to be in competition with the theory that God exists, although it is seen by many to be so. The theories occupy entirely different niches, in a sense, and thus are not mutually exclusive, just as a deer and a tree are not mutually exclusive. They serve different functions. The theory of evolution is an attempt to understand the world around us through observation and reasoning, while the theory of the existence of God is meant to comfort and support us through life. The first tries to explain the world through natural laws, while the second explains where those laws came from. The first is falsifiable and thus falls under the domain of Science, whereas the second is non-falsifiable and thus entirely outside the domain of Science. The proof for evolution is observed, while the proof for God is felt. The two theories do not compete.

References

1) Clark, Robert E. D. Darwin: Before and After. London: The Paternoster Press, 1948
2) Fichman, Martin. Evolutionary Theory and Victorian Culture. Amherst, New York: Humanity Books, 2002
3) Mayr, Ernst. What Evolution Is. New York, NY: Basic Books, 2001


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