In this article, I suggest an argument that seems to show a conflict between the reflection principle and conditionalization. In particular, I show that when the reflection principle is formulated in a standard way, the principle conflicts with Jeffrey conditionalization. And it is argued that the source of the conflict resides in an ambiguity of the standard formulation. Furthermore, I attempt to rescue the principle using Bayes factors. That is, I suggest a new formulation of the principle so as to avoid the conflict.
I would like to thank the anonymous referees for their invaluable suggestions. And I owe special debts to Inkyo Chung and Alan Hájek for their detailed and insightful comments.