 A second, more general challenge for the prediction-as-deduction approach is posed by statistical hypotheses. Suppose we want to test the theory that only 50% of ravens are black. This hypothesis entails nothing about the color of an individual raven; it might be one of the black ones, it might not. In fact, even a very large survey of ravens, all of which turn out to be black, does not contradict this hypothesis. It’s always possible that the 50% of ravens that aren’t black weren’t caught up in the survey. (Maybe non-black ravens are exceptionally skilled at evasion.)