 Now, suppose we want to add a new connective \(\rightarrow\) to our language to represent ‘If …then …’. When should you believe a sentence of the form \(A \rightarrow B\)? The classic answer comes from an idea of Ramsey’s: that we decide whether to accept \(A \rightarrow B\) by temporarily adding \(A\) to our stock of beliefs and then seeing whether \(B\) follows (Ramsey 1990 [1929]). This idea yields a principle called the Ramsey Test: