  That is, a degree of belief in \(q\) given \(p\) exists only when the degree of belief in \(p\) is non-zero. Ramsey does make a few remarks about counterfactuals, noticing the ‘subtle syntactic variations’. For instance, “If he was there, he must have voted for it (for it was passed unanimously), but if he had been there, he would have voted against it (such being his nature)” (1929b, [FM] 249). (Here we have an early precursor of the Oswald-Kennedy pair: if Oswald didn’t do it, someone else did; but if Oswald hadn’t done it, no one else would have; see Adams 1970.) There are a few remarks about counterfactuals in Ramsey’s paper but no settled view of them is presented.