Abstract: What is the nature of one’s justification to use a logical principle such as Modus Ponens in reasoning? It is widely agreed amongst epistemologists of logic that such justification cannot be internalist. One key reason offered for this view is that internalist accounts of justification are susceptible to Carroll-style regresses. In this talk, I examine this claim and argue that internalist accounts of justification are not open to such regresses. I further argue that the sorts of externalist accounts of the justification of logical principles typically put forward as alternatives are inadequate.