An argument whose conclusion C is essential evidence for one of its premises can provide its target audience with justification for believing C. This is possible because we can enhance our justification for believing a proposition C by integrating it into an explanatory network of beliefs for which C itself provides essential evidence. I argue for this in light of relevant features of doxastic circularity, epistemic circularity, and explanatory inferences. Finally, I confirm my argument with an example and respond to (...) objections. (shrink)

In this essay, I consider an evolutionary debunking argument (EDA) that purports to undermine the epistemic justification of the belief in the reliability of our belief-forming processes, and an evolutionary vindicating argument (EVA) that seeks to establish that such a belief is epistemically justified. Whereas the EDA in question seems to fall prey to crippling self-defeat, the EVA under consideration seems to fall prey to vicious circularity. My interest in those arguments and the problems they face lies in what they (...) might tell us about the possibly aporetic nature of reason. For, if we take the EDA and the EVA in question to consist of true or plausible premises and valid inferences at which we arrive through a meticulous use of reason, then their falling victim to either crippling self-defeat or vicious circularity might be regarded as a sign that, when we push rational reflection on the reliability, or lack thereof, of our belief-forming capacities to the limit, we end up in a situation of aporia from which there seems to be no escape. (shrink)

This paper discusses some of the ways in which circular definitions and circular explanations entail or fail to entail infinite regresses. And since not all infinite regresses are vicious, a few criteria of viciousness are examined in order to determine when the entailment of a regress refutes a circular definition or a circular explanation.