 Why should we update our subjective probabilities according to strict or Jeffrey conditionalization? Dutch-book style arguments for strict conditionalization are given in Teller (1973) and Lewis (199) and extended to Jeffrey conditionalization in Armendt (1980). For more, see Skyrms (1987, 2006). Leitgeb and Pettigrew (2010b) present an accuracy argument for strict conditionalization (see also Greaves and Wallace, 2006) as well as an argument for an alternative to Jeffrey conditionalization. For an overview, see the entry on  epistemic utility arguments for probabilism.