 That’s the special case of the New Principle for an agent with no inadmissible evidence. The general case follows from this special case. In general, assuming the agent has no inadmissible evidence, the rational credence in A given E is the expected value, given E, of the chance of A given H ∧ T. That is, where C is the agent’s credence function, and P is the chance function, it should be the sum across all possible combinations of H and T of C(H ∧ T | E)P(A | H ∧ T).