exception proves the rule, the. A widely misunderstood expression. As a moment's thought should confirm, it isn't possible for an exception to confirm a rule – but then that isn't the sense that was originally intended. Prove here is a 'fossil' – that is, a word or phrase that is now meaningless except within the confines of certain sayings {'hem and haw', 'rank and file' and 'to and fro' are other fossil expressions}. Originally prove meant 'test' {it comes from the Latin probo, 'I test'}, so the exception proves the rule meant – and really still ought to mean – that the exception tests the rule. The original meaning of prove is preserved more clearly in two other expressions: 'proving ground' and 'the proof of the pudding is in the eating'.
( Bill Bryson )
[ Troublesome Words ]
www.QuoteSweet.com