Sunday, March 3, 2013

Why the natural sciences rely on affirming the consequent (and that's OK!)

Last weekend, I discussed a paper by Graur et al., which (among many other criticisms and insults) accused the ENCODE consortium of basing certain interpretations on a fallacy in deductive logic called "affirming the consequent." I pointed out how bizarre that criticism was, because "affirming the consequent" is actually a necessary and justified part of reasoning in the natural sciences.

Many readers seemed to be surprised by and skeptical of this claim, and some probably thought it proof of my insanity. I must, first and foremost, once again beg such skeptics to read Jaynes' outstanding book. The first few chapters are actually available as a free pdf, but the whole book is really worthwhile. If you're an academic, you can probably find the book in your library system.

Understanding, however, that the urging of an apparent madman may not be adequate motivation, I thought I'd try to explain a bit more why this is, actually, the case.