Myth: Life obviously had an intelligent designer.
Fact: The appearance of design is actually biological efficiency enhanced by natural selection.
Life has indeed been designed, but by whom or what is the central controversy. Creationists believe it was an intelligent designer, namely, God; evolutionists believe it was a driving force of nature, namely, natural selection. Natural selection works when life forms with advantageous survival traits live long enough to breed, therefore passing on those traits to the next generation. Life forms with weaker traits die before breeding, and therefore disappear from the gene pool. Genetic diversity results in slight variations of these hereditary traits from generation to generation, which allows a species to adapt to the changing demands of a changing environment. This results in a suitability between life form and environment that many people mistake for intelligent design.
In the 18th century, the scientific world was neck-deep in clues of evolution, but a simple counter-argument had stopped scientists from accepting a theory on evolution. This was Bishop Paley's argument that life had obviously been designed. For example, if a person who had never seen a watch before was walking through the woods and discovered one, he would know by its interdependent features and functions that it had been designed and manufactured by another human. The same point can be made of life. The human eye, for instance, exhibits all the evidence of design: the transparency of the cornea, the adjustability of the pupils for light, the curvature of the lens for focus, all cooperate together to serve sight. This interdependency to serve a greater function could only be the product of design. Design must have a designer. And that designer, Paley argued, is God.
The 18th century Scottish philosopher David Hume could not explain the appearance of design in nature, but he was the first to point out the flaw in Paley's logic. The problem is one of choosing the correct analogy. He pointed out that the universe more resembles a living organism than a mechanical watch -- which indicates that the universe must have started as a fetus in a cosmic womb! Other scholars also lampooned Paley's argument; Voltaire argued that noses must have been designed to hold up glasses, and that bunny rabbits must have been given white tails so they could be easier to shoot. The idea of design was so thoroughly and effectively ridiculed that theologians of the time actually stopped using it as an argument, although, curiously enough, it would resurface in the 20th century.
Darwin essentially agreed that life had been designed, although not necessarily by the designer that Paley evoked. Darwin's advance on the argument was that the designer did not have to be an intelligent being, but could also be a driving force of nature. Consider the example of horse-breeding. A rancher can select any trait among his horses that he would like to emphasize -- for example, small size. By breeding his smallest horses together, he will eventually obtain a line of miniature horses. Evolutionists cite this as proof that species can change as a result of selective breeding. Creationists respond -- quite rightly -- that the process needs a designer, in this case the rancher. But evolutionists point out that the same process happens in nature. Imagine a land separated by a mountain range a thousand miles long. Horses are originally found only on one side of the mountain range, which is sufficiently tall to prevent passage to the other side. But suppose the horse population finds a craggy pass in the mountains, only so narrow that only the smallest of horses can pass through. Of course, young horses don't like to be separated from their parents, so large horses and their offspring would remain on one side the pass, while small horses and their offspring would migrate to the other side. There, they would establish their own population of small horses, which would then breed and produce offspring who also turn out to be small. Thus, a demand of the environment changes the species.
Darwin's fame resides in the fact that he identified the forces of nature which design life. Instead of an intelligent being selecting which members should breed with each other for certain characteristics, nature would select for these characteristics, hence the term "natural selection." Darwin identified three factors responsible for natural selection: