Tuesday, March 4, 2008

Abductive Reasoning

Evolution's explanation for life on earth is said to be "good science." Is this pronouncement sufficient to establish the truth of the tenets of evolution, we may ask? Scientists have discussed the effectiveness of various methods of science discovery for several centuries. They also discuss, and often disagree, on how to interpret their data and the results of their experiments. This is a healthy process because it enables them to correct errors. The self-correcting nature of the process of science is one of its many strengths. Books on science philosophy would fill all the shelves in my library, and many more.

If you look for descriptions of "scientific method" you will almost certainly find one, two, or all three of these terms: induction, deduction, and abduction. Charles S. Peirce (1839-1914), giant of American philosophers, placed induction and deduction into a complementary relationship as cornerstone methods of science discovery. Then he added "abduction" to the mix. This three-fold blend is a foundation of modern science, but not many non-scientists know how these terms apply to today's science.

Let's discuss a few things science philosophers write about. Abductive reasoning is "an inference to the best explanation." We observe natural phenomena, collect evidence, study facts, and organize data. Then we propose the most plausible explanation for what we see. In Peirce's three-pronged method of scientific inquiry, abduction is not the concluding activity, but rather a starting point, an initial conjecture about what is going on. This conjecture originates in the mind of the scientist, perhaps a result of his past experience, and then guides the inductive/deductive activities to follow. Therefore, the scientist's mindset or bias may drive the way he approaches and proceeds with his work, as well as the conclusions he draws.

Supporters of the concept of evolution look at the fossil record and "see" evolution. Thereafter, their research is often selectively reported and interpreted in order to support their initial concept. Charles Peirce coined the term "fallibilism," the idea that the conclusions of science are always tentative and subject to revision. In view of the self-correcting nature of science, the discovery of contradictory evidence, or in some evolutionary biology cases, lack of evidence, does not seem to tilt evolutionists away from their staunchly held views. We've spoken about fossil evidence that displays the sudden onset of many new forms without intermediate transitionals. By applying abductive reasoning at the end of the evidence-gathering process, we may rationally infer that transcendent creation events may trump evolution as the best explanation for what we observe in the fossil history of earth life.