CS Lewis, on Emotion in Thinking
"Certainly we were talking too lightly and easily about these things a fortnight ago.... One used to be told as a child: 'Think what you're saying.' Apparently we need also to be told: 'Think what you're thinking.' The stakes have to be raised before we take the game quite seriously. I know this is the opposite of what is often said about the necessity of keeping all emotion out of our intellectual processes - 'you can't think straight unless you are cool.' But then neither can you think deep if you are. I suppose one must try every problem in both states." Pg 45.