In a recent editorial Marsha Sutton wrote about controversies surrounding the theory of evolution.
Ms. Sutton suggested that disputing the theory of evolution is like disputing the theory of gravity. Isn’t this just what Einstein did, rejecting the theory of gravity in favor of a better model, based on space-time deformation? This example implies the opposite of what I believe Ms. Sutton intended. The example indicates that the theory of evolution, as we know it, could at some point be replaced by something radically different.
The word “science” is often used indiscriminately. For example, the science of evolution and the science of physics are different kinds of knowledge. Evolution is partly history, in which an explanation is constructed that fits evidence from the past. Physics requires a kind of experimental repeatability that is not possible for the basic tenets of evolution. Evidence for a theory in physics necessarily follows from the theory. Evidence for the theory of evolution need only be consistent with it. Criticisms of evolution, as misguided as they may be, do not necessarily mean that one has doubts about science in general.
In a subsequent letter, Dr. Srinivasan congratulated Ms. Sutton and refers to evolution as a “simple and fully resolved fact.” Statements of fact are direct descriptions of observations. From the same facts, it is possible to derive a multitude of inferences. We hold inferences with varying degrees of confidence. An inference does not turn into a fact because it is consistent with the facts. An inferred model, such as the theory of evolution, may have explanatory power and be an effective framework for further exploration and the organization of knowledge, but it is not a fact. I am reminded of the saying “all models are wrong, but some are useful.” Resorting to phrases such as “scientific fact” is a misleading equivocation.
For hundreds of years Newtonian physics was viewed as a “fact.” The same had been true of Aristotle’s physics. The lessons of Einstein, and earlier Galileo, require more humility. Theories and models are necessarily limited views of reality and are not the same thing as the reality which they describe. The friction surrounding the theory of evolution might be defused if it were described for what it is: an effective working model that has been inferred from a body of data. It is neither true nor false and it is not a fact. Teaching otherwise can be confusing, dogmatic, and anti-scientific.