Full Idea
Russell often treated propositions as facts, but discovered that correspondence then became useless for explaining truth, since every meaningful expression, true or false, expresses a proposition.
Gist of Idea
If propositions are facts, then false and true propositions are indistinguishable
Source
comment on Bertrand Russell (The Principles of Mathematics [1903]) by Donald Davidson - Truth and Predication 6
Book Reference
Davidson,Donald: 'Truth and Predication' [Belknap Harvard 2005], p.125
A Reaction
So 'pigs fly' would have to mean pigs actually flying (which they don't). They might correspond to possible situations, but only if pigs might fly. What do you make of 'circles are square'? Russell had many a sleepless night over that.
Related Idea
Idea 6091 Propositions don't name facts, because each fact corresponds to a proposition and its negation [Russell]