A new arrival, Kouran, recently challenged our conventional use of the label "rational" to describe various systems. The full thread is here, and it doesn't summarize neatly, but he observes that we often use "rational" in the context of non-intellectual, non-cognitive, etc. systems, and that this is an unconventional use of the word.

I read the comment by Kouran and while he or she had some valid points they are for most part already points assumed by our actual conventions here and so do not particularly apply as criticism. Mind you this is from a perspective of someone already inclined to consider some usages of 'rational' as a violation of convention.