"Sounds to me like Lewis focused on what he knew the most about and politely evaded the man's attempts to draw him into an argument he wasn't trained for -- in the sort of display of good sense we've come to expect from Lewis." ~ Taliesan
J.P. Holding also displays that sort of good sense, but makes the same point that Lewis made about the most rabid defenders of Evolution:
Choking on Pretzel Logic
http://www.tektonics.org/af/evologic.html
Why I Don't Buy (or Sell) the Evolution Story
James Patrick Holding
Editing Note: I have to say that since I first wrote this article, I'd say that I have even greater inclinations against evolution because of the number of proponents I have met who uncritically spout such nonsense as, "Jesus evolved from Mithra." But keep this one online as a secondary reason.
I wish a big dollop of such good sense could be slathered on a bunch of creationist freepers, who want to argue in fields where they are not trained.
In principle there is nothing wrong with that...scientists are wrong to say you can't criticize them unless you are a scientist. This is nothing more than the argument from authority they claim to abhor.
There is also nothing wrong with laypeople criticising the logic of evolutionists' reasoning. Logic is logic. There is no special science logic. Scientists who sniff at lawyers (Coulter, Johnson) for criticising their logic should, rather, defend their logic. (But the problem is that -- like Coulter -- these critics will often shift from a logical argument in paragraph to a scientific argument in the next, and can't apparently tell the difference.)
But scientists are of course right to insist that if you are going to enter the arena of scientific argument, you must demonstrate the level of knowledge a professional has a right to expect from a SERIOUS amateur. Most people who are trained in a subject don't resent at all an amateur questioning them and even offering a contribution to the field, but an ignorant and arrogant amateur is just intolerable.
I am a Christian who believes the Bible is literally true, and I am not trained in the sciences. But I find the creationist side of the argument, as it is represented here on FR, so embarassing I usually don't even go into those threads.
I'd urge Lewis' attitude on many here.