Fallacies do not cease to be fallacies because they become fashions.
-- G. K. Chesterton
The quote is good; but I have a knee-jerk reaction against all rationality quotes by Chesterton, who cleverly confused social conservatism with rationality in the minds of so many people.
A monthly thread for posting rationality-related quotes you've seen recently (or had stored in your quotesfile for ages).