Charles Chihara has presented a problem he claims Bayesian confirmatio
n theory cannot handle. Chihara gives examples in which he claims the
change in belief cannot be construed as conditionalizing on new eviden
ce. These are situations in which the agent suddenly thinks of new pos
sibilities. I propose a solution that incorporates the important ideas
of Bayesian theory. In particular, I present a principle which shows
that the change of belief in Chihara's example is due to simple condit
ionalization.