We sometimes commit ourselves to the pursuit of a goal in the face of uncertainty that we will achieve it. Even as we lay our plans to succeed in such cases, it can be sensible at the same time to plan for failure -- to make a plan B. Can our web of practical commitments be internally consistent when we plan in this way for two different, incompatible futures? I will argue that on the right way of thinking about what a plan B is, and how it is related to one's plan A, there need be no logical inconsistency between primary plans and backup plans. That said, we often do take certain kinds of backup planning to be in tension with complete, sincere commitment to one's primary plan. A fuller story is needed to capture the rational space our backup plans can occupy. I aim to take some initial steps in offering such an account.
