 Plain Conditionalization.  Suppose that \(\varrho(\cdot)\) is your ranking function at time \(t\) and that \(\varrho(A),\varrho(\neg A) \lt \infty\). Furthermore, suppose that between \(t\) and \(t^\prime\) you become certain of \(A\) and no logically stronger proposition. Then, your ranking function at time \(t^\prime\) should be \(\varrho(\cdot\mid A)\). 