 We’ll explain the New Principle by starting with a special case of the old Principle. Let T be the ‘theory of chance’ for the world, the conjunction of all history-to-chance conditionals. And let H be the history of the world to t. Assuming T is admissible, the old Principal Principle says that the credence in A given H ∧ T should be the chance of A at t. The New Principle says that the credence in A given H ∧ T should be the chance of A given T at t. That is, where C is the agent’s credence function, and P is the chance function, and the agent has no inadmissible evidence, it should be that C(A | H ∧ T) = P(A | T). This compares to the old principle, which held that C(A | H ∧ T) = P(A).