Benjamin Bewersdorf (Konstanz) gives a talk at the MCMP Colloquium (23 January, 2013) titled "Garber and Field Conditionalization ". Abstract: The most influential formal account on rational belief change is Jeffrey conditionalization. Given a plausible assumption on the role of experiences for belief change, Jeffrey conditionalization turns out to be incomplete. Field tried to complete Jeffrey conditionalization by adding an input law to it. But, as Garber has pointed out, the resulting theory has a serious weakness. In the following, I will both generalize Garber's objection against Field's account and show how Field's account can be modified to avoid it.