I'm trying to work through Donald Davidson's 'Truth and Meaning' but am blocked from the start by the fact that he uses an obscure notation near the beginning, that even someone like me who can understand first-order logic can't interpret in this context. I quote: "But now suppose that 'R' and 'S' abbreviate any two sentences alike in truth value. Then the following four sentences have the same reference: 1) R 2) x̂(x = x.R) = x̂(x = x) 3) x̂(x = x.S) = x̂(x = x) 4) S " I've never encountered the schema 2) and 3) before, so I'm just not sure what they mean, especially in this philosophy of language context. I'm an autodidact so don't have access to many other resources!

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