As you've probably heard from other ScienceBlogger's, that paragon of
arrogant ignorance, Dr. Michael Egnor, is back at it again - and he's abusing
the language of logic in a way that really frustrates me. I've written
about this before, but the general topic recently came up in comments, so
I thought I'd bump it up to the top, along with another slap aimed at Egnor.
For those who don't know, Dr. Egnor is a brain surgeon at SUNY Stonybrook - an excellent school, and Dr. Egnor is, from all information I've heard, an outstanding surgeon. In his free time, he blogs for the Discovery Institute, using his
status as an accomplished brain-surgeon to try to boost the bullshit spewing out of DI.
One of Dr. Egnor's favorite attacks in his anti-evolution screeds always makes me think of a line from one of my favorite movies: "Hello, my name is Inigo Montoya, you killed my father, prepare to die". Oops, no, not that one. (Sorry, couldn't resist.) The real line is "You keep using that word. I do not think it means what you think it means".
You see, what Egnor keeps doing, over and over again, is arguing that
evolution is just a tautology, and that therefore it's meaningless. He
defines evolution as the statement "that which survives, survives". He almost never gets through one of his posts without that accusation in one form or another: evolution is a tautology, and that implies that it's meaningless and worthless as an explanation of anything.
Leave aside for the moment the fact that he mis-states the key premise of evolution. That's a huge, obvious, and deliberate mistake, but let's just ignore it for now. Instead, I'd like to just look at the problem with his statement about tautologies. What exactly is a tautology? And does
criticizing something as "just a tautology" actually make any sense?