To give a reason for anything is to breed a doubt of it. William Hazlitt
The theory of probabilities is basically only common sense reduced to a calculus. It makes one estimate accurately what right-minded people feel by a sort of instinct, often without being able to give a reason for it. Pierre-Simon Laplace
Senators could seldom give a reason for obstruction. In every hundred men, a certain number obstruct by instinct, and try to invent reasons to explain it afterwards. Henry Adams
I always say, 'If you can't give a reason for the banana peel being in the alley, then don't have the comic slide over it.' Do you understand what I mean? First explain how the banana peel got there quickly. And then there's a reason for all the comedy. Elaine Stritch