Defenders of Inference to the Best Explanation (IBE) claim that explanatory factors should play an important role in empirical inference. They disagree, however, about how exactly to formulate this role. In particular, they disagree about whether to formulate IBE as an inference rule for full beliefs or for degrees of belief, and, if it is formulated as a rule for degrees of belief, how this rule relates to Bayesianism. In this essay I advance a new argument against non-Bayesian versions of IBE that arises when we are concerned with multiple levels of explanation of some phenomenon. I show that in many such cases, following IBE as an inference rule for full belief leads to deductively inconsistent beliefs, and following IBE as a non-Bayesian updating rule for degrees of belief leads to (synchronically) probabilistically incoherent degrees of belief.Proponents of Inference to the Best Explanation (IBE) claim that our inferences should give explanatory considerations a central role. Beyond this general agreement, however, they have differed on precisely how explanation should inform inference. A particular area of controversy has been the relation of IBE to Bayesianism. Should IBE be formulated in terms of full beliefs, as in traditional epistemology, or in terms of degrees of belief, as in Bayesian epistemology? If it is formulated in the latter way, is it compatible with Bayesian epistemology?In this essay I advance a new argument against non-Bayesian formulations of IBE. This includes both traditional formulations of IBE in terms of full belief and non-Bayesian formulations of IBE in terms of degrees of belief. I show that in some instances, IBE for full belief licenses deductively inconsistent inferences from the same evidence. In similar instances, following non-Bayesian IBE updating rules for degrees of belief leads to probabilistically incoherent credences.