A Side of Bacon

Karl Popper was a well-known philosopher of science who worked in the middle of the last century. He got in trouble for writing that Darwinism is not really a scientific theory because natural selection is an all-purpose explanation that can account for everything (and therefore is not falsifiable--more on that tomorrow). That he got in trouble for saying this does not necessarily mean he was wrong.

If an idea can be stretched to account for every conceivable event, what is its real power of explanation? It actually doesn't help. According to Popper, the only genuine theory is one which makes risky predictions, i.e., it goes out on a limb to predict something will happen according to this theory, risking being proved wrong if the prediction is incorrect. For example, one of the key predictions Albert Einstein made in his general relativity theory is that light from distant stars would be bent by large gravitational fields. A few years later, other scientists made the observations that confirmed Einstein's prediction.

This follows the Baconian model of science, otherwise known as induction. According to this model, the scientist begins with experimental data and draws conclusions from what he has observed. The theory is then verified by accumulating corroborative evidence. There are admittedly problems with this model, often centered on the reliability of our observations and our ability to discern accurately cause and effect--this was the crux of David Hume's skepticism about causality. The Baconian model also does not reflect what actually transpires. Scientists typically begin with an idea or hypothesis and then carefully design experiments to test the accuracy of the idea, a sort-of artificial mode of observation but one that carries distinct advantages.

The difficulty for Darwinian evolution and for evolutionary biologists is that macroevolution can't be made to fit in this construct, particularly because naturalistic evolution's foundational concepts have been declared true by definition (axioms) and are therefore not subject to testing.