For the most part, characters in the Adventures of Huckleberry Finn are made fools by other characters. Pranks, cons, tricks, and deceptions seem to be everyone’s stock and trade in this novel, which means a healthy supply of gullible nitwits is in demand. And there seems to be no shortage. As one character succinctly remarks (shortly before being made into an utter fool himself), the group of fools in any town always comprises the majority. True – at least as far as the Adventures of Huckleberry Finn is concerned.
The foolishness of "the mob" in Adventures of Huckleberry Finn serves as a parallel to the folly of the whole of Southern culture for its beliefs on slavery.
"Foolishness" with regards to intellect is inversely proportional to wisdom and morality in the characters of Adventures of Huckleberry Finn. The smarter the man, the more immoral.