 Let us say that a subject s doubts q just in case s either disbelieves or withholds belief about q, namely refrains from both believing and disbelieving q after deciding about q. s’s doubting q should be distinguished from s’s being open minded about q and from s’s having no doxastic attitude whatsoever towards q (cf. Tucker 2010a). Let us say that a deductively valid argument from p to q has the power to resolve doubt about its conclusion just in case it is possible for s to be rationally moved from doubting q to believing q solely in virtue of grasping the argument from p to q and the evidence offered for p.