Why Darwin Matters_ The Case Against Intelligent Design - Michael Shermer [5]
Darwin matters not only because his theory changed the world and reconfigured our position in nature, but because he launched a new and profound understanding of biology and science that has served future generations. Of the three intellectual giants of that epoch—Darwin, Marx, and Freud—only Darwin is still relevant for the simple reason that his theory was right, and the scientific evidence continues to support and refine it. In the memorable observation by geneticist Theodosius Dobzhansky, “Nothing in biology makes sense except in the light of evolution.”11
THE FACTS OF EVOLUTION
The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth. As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications.
—Charles Darwin, On the Origin of Species, 1859
The theory of evolution has been under attack since Charles Darwin first published On the Origin of Species in 1859. From the start, its critics have seized on the theory of evolution to try to undermine its facts. But all great works of science are written in support of some particular view. In 1861, shortly after he published his new theory, Darwin wrote a letter to his colleague, Henry Fawcett, who had just attended a special meeting of the British Association for the Advancement of Science during which Darwin’s book was debated. One of the naturalists had argued that On the Origin of Species was too theoretical, that Darwin should have just “put his facts before us and let them rest.” In response, Darwin reflected that science, to be of any service, required more than list-making; it needed larger ideas that could make sense of piles of data. Otherwise, Darwin said, a geologist “might as well go into a gravelpit and count the pebbles and describe the colours.”1 Data without generalizations are useless; facts without explanatory principles are meaningless. A “theory” is not just someone’s opinion or a wild guess made by some scientist. A theory is a well-supported and well-tested generalization that explains a set of observations. Science without theory is useless.
The process of science is fueled by what I call Darwin’s Dictum, defined by Darwin himself in his letter to Fawcett: “all observation must be for or against some view if it is to be of any service.”
Darwin’s casual comment nearly a hundred and fifty years ago encapsulates a serious debate about the relative roles of data and theory, or observations and conclusions, in science.2 In a science like evolution, in which inferences about the past must be made from scant data in the present, this debate has been exploded to encompass a fight between religion and science.
Prediction and Observation
Most essentially, evolution is a historical science. Darwin valued above all else prediction and verification by subsequent observation. In an act of brilliant historical science, for example, Darwin correctly developed a theory of coral reef evolution years before he developed his theory of biological evolution. He had never seen a coral reef, but