 Jackson came to realise, however, that there are assertable conditionals which one would not continue to believe if one learned the antecedent. I say “If Reagan worked for the KGB, I’ll never find out” (Lewis’s example (1986, p. 155)). My conditional probability for consequent given antecedent is high. But if I were to discover that the antecedent is true, I would abandon the conditional belief, rather than conclude that I will never find out that the antecedent is true. So, in Jackson’s later work (1987), robustness with respect to \(A\) is simply defined as \(\mathbf{p}_A (A \supset B)\) being high, which is trivially equivalent to \(\mathbf{p}_A (B)\) being high. In most cases, though, the earlier explanation will hold good.