I can recall one of the very first creationist types I met, way back when I was in the navy. He proudly proclaimed that he knew evolution was false, because a dog would never give birth to a cat. It floored me that someone with a tech background could have so completely failed in both the application of logic and in having the requisite knowledge to be preaching on the subject.

Through the years I’ve seen far too many similar argument, in which the demand for some evidence, either unreasonable at its face or required of the strawman version of the theory, is made, and the inability to provide said evidence is immediately (and erroneously) taken as the death knell of the theory in question. Basically these people are insisting on seeing a smoking gun, when the victim has been quite obviously stabbed to death.

Here’s a nice article that addresses this phenomenon:

Less Wrong: You’re Entitled to Arguments, But Not (That Particular) Proof

(ceteris paribus is a Latin phrase used in the post, and one I can’t recall having seen before. It means “all other things being equal” and has nothing to do with stories about whales)

And in a burst of evolutionary irony, the post has some useful appendices