 The observation that the first raven is black is consistent with both hypotheses \(H_1 =\) “all (observed) ravens are black” and \(H_2 =\) “some (observed) raven is not black”. The observation that the first raven, or any raven, is white falsifies the hypothesis \(H_1\) and entails the hypothesis \(H_2\). The entailment is illustrated by the gray fan structure, which means that after the observation of any white raven, the hypothesis \(H_1\) is correct for any extending complete data sequence that records the color of all further observed ravens.