Consider Mr. Spock of Star Trek, a naive archetype of rationality. Spock's emotional state is always set to "calm", even when wildly inappropriate. He often gives many significant digits for probabilities that are grossly uncalibrated. (E.g: "Captain, if you steer the Enterprise directly into that black hole, our probability of surviving is only 2.234%" Yet nine times out of ten the Enterprise is not destroyed. What kind of tragic fool gives four significant digits for a figure that is off by two orders of magnitude?) Yet this popular image is how many people conceive of the duty to be "rational"—small wonder that they do not embrace it wholeheartedly.
— Eliezer Yudkowsky, Why Truth? And...
Logic could only take you so far, then you had to get out and walk.
— Terry Pratchett, The Last Continent
Chaos and optionality, which to these days governed the historical and political ideas, have been replaced by a stunningly uniform and harmonious scientific theory.
— Vladimir Illich Lenin
"I cannot - yet I must! How do you calculate that? At what point on the graph do 'must' and 'cannot' meet?"
—Ro-Man, Robot Monster
"Logic, logic, logic. Logic is the beginning of wisdom, not its end."
"Logic is like the sword — those who appeal to it, shall perish by it."
"Logic is a poor guide compared with custom."
"Logic, like whiskey, loses its beneficial effect when taken in too large quantities."
"I've never been a fan of books. I don't trust them. They're all fact and no heart."
—Stephen Colbert, parodying this trope
Bob: It was really more foolish than that. I used to ask myself — why doesn't she love me?
Mary: You asked yourself - that?
Bob: All the time.
Mary: (Throws bedclothes on sofa, exploding.) That's why I hate intellectuals! They're all so dumb!
"Like all cyborgs I am unhampered by emotions unless required otherwise by lazy scriptwriters."