The Complexity of the Evolution Debate
A week ago I reviewed The Evolution Controversy by Thomas B. Fowler and Daniel Kuebler. One of the things this book does extremely well is to identify the scientific points in controversy among the four main schools of thought on human origins: Neo-Darwinism, Meta-Darwinism, Creationism and Intelligent Design.
A brief consideration of the principal points in dispute provides a good introduction to the complexity of the whole topic. Fowler and Kuebler identify eight such points:
- Common Descent: All scientists point to striking similarities among organisms. But does this data demand a theory of common descent of higher from lower life-forms, or is a common design plan an equally valid inference?
- Random Mutations: Again, everyone agrees that mutations occur in nature. But are they limited to the recombination of existing genetic data or can they produce the kind of new biological information required for the emergence of new species?
- Natural Selection: Is natural selection more than a tautology (only the fittest survive; if these survived, they are the fittest)? If natural selection means something, however, even Darwinian scientists disagree markedly over whether it is a sufficient filter for random mutations to result in large-scale change.
- Microevolution or Macroevolution: Scientists in all schools accept evolutionary change within species (microevolution) but they disagreee profoundly on whether the same mechanisms which drive these minor changes can actually cause the development of higher taxa of substantially different species (macroevolution).
- Age of the Universe: All schools except Young Earth Creationists generally accept the great age of the universe and of the earth postulated in standard geological time measurements. But there is some evidence which points toward a young earth, and some scientists believe that geological strata can be explained without great age. Even with the longest age projections, many scientists believe the time period is too short for the evolution of certain complex organs. If the earth is too young, the most numerous school, Neo-Darwinian evolution, fails.
- Scope of Naturalistic Explanations: Most scientists agree that methodological naturalism is central to science. The idea is that scientists qua scientists must seek natural explanations of the phenomena they observe; otherwise they aren’t doing science. But this does not mean most scientists agree that natural explanations suffice for everything. That’s naturalism pure and simple, or materialism. Scientists in all schools have pointed out that the wrong kind of naturalism can blind theorists to all but the ideas that “fit”.
- The Nature of a Scientific Theory: There are ten commonly accepted criteria for a sound scientific theory. That’s too many criteria to examine here, but the various schools battle over which criteria are really found in their respective theories. Falsifiability? Verifiability? Retrodiction? Prediction? Repeatability? And so on.
Fowler and Kuebler also identify eleven logical fallacies that are used with alarming frequency by careless proponents of every school, further muddying the waters: tautology; circular reasoning; analogy; just-so stories; incredulity; psychological plausibility; extrapolation; claiming liabilities as assets; argument from authority; retreat into unknowability and untestability; and explaining by naming.
Clearly, before we even begin to introduce the evidence, we have a great many tough questions. If you thought this topic was simple, please forgive me for poisoning your world. The antidote is to read the book.
[Thomas B. Fowler & Daniel Kuebler, The Evolution Controversy: A Survey of Competing Theories. Baker Academic, Grand Rapids, MI, 2007. 382 pp. Paper. $24.99. Available from www.bakeracademic.com and Amazon for under $20, or ask your local bookseller. For my review, see Evolution: The Missing Link.]
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