 I shall discuss only briefly a recently published book by Timothy Williamson, Suppose and Tell (2020). Williamson accepts that the suppositional procedure—suppose the antecedent, and on that basis come to a judgement about the consequent—is our fundamental, primary method of conditional judgement, an essential part of our cognitive equipment. As uncertainty is often involved, he accepts that it is appropriate to theorize about this process in terms of conditional probabilities. This is what he calls the heuristics of conditionals (not to be confused with semantics). Heuristics are part of our cognitive and psychological apparatus, “fast and frugal”, immensely useful and valuable, but typically imperfect. In this case, they lead to subtle logical problems, he argues (ch. 3), broadly of the same kind as Lewis’s triviality results—indeed, to inconsistencies. An assessment of these arguments will have to wait for another occasion. Nevertheless, he claims, they are useful and valuable for our everyday conditional thinking. 