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.
"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.