'102. One can't proceed from the informal to the formal by formal means.'
--Alan Perlis, Epigrams in Programming
Cox's theorem seems to reduce the gap between the formal and the informal, by deriving probability theory from axioms that seem easier to informally assess.
This is our monthly thread for collecting these little gems and pearls of wisdom, rationality-related quotes you've seen recently, or had stored in your quotesfile for ages, and which might be handy to link to in one of our discussions.