 A few authors identify propositions with properties: for example, Lewis  (1986b,  53–4) holds that the proposition that some swans are blue is being a world containing a blue swan. Others (e.g. Bealer  1982)  reject this identification, but still treat propositions as property-like: as binary relations stand to the number 2 and monadic properties stand to 1, propositions stand to 0. Given either of these views, the notion of a natural proposition should raise no new  difficulties.[6]