 The probability of snow is around 0.5; and we reckon (on the suppositional procedure), it’s around 0.2 that the road will be impassable if it snows. According to the truth function, the conditional gets 0.6. Then, as forecasts are updated, the probability of snow decreases. Nothing else changes. On the truth-functional semantics, the probability of our conditional goes up as the probability of snow goes down: when the probability of snow goes down to 0.25, the probability of (*) is 0.8 on the truth-functional reading, although it remains at 0.2 on the suppositional approach. Williamson says that our suppositional procedure errs “on the side of caution” (p. 104) by generating lower probability values than the truth-functional conditional. It is hard to see why, as the probability of snow decreases, we become more risk-averse, and make larger errors on the side of caution. 