Fitelson proposes the following principle: "If E constitutes conclusive evidence for H1, but E constitutes less than conclusive evidence for H2 (where it is assumed that E, H1 and H2 are all contingent), then E favors H1 over H2."
The principle is false. You witness Jones being shot and after approaching you observe that he is dead. Let E be this evidence. Let H1 be the hypothesis that Jones is dead. Let H2 be the hypothesis that Jones has been killed. Then E is conclusive evidence for H1 and less than conclusive evidence for H2. (That you observed that Jones is dead entails H1. But on one reading of "Jones being shot", E is compatible with the hypothesis that Jones was already dead when he was shot—we can say "He was shot after he died." And on any reading, E is compatible with Jones having died of some other cause, coincidentally.) But it is wrong to say that E favors the hypothesis that Jones is dead over the hypothesis that Jones was killed.