Scepticism, Explanationism, and Epistemic Closure

In a delightful little book on several varieties of philosophical scepticism, Mario Alai writes that relevant alternatives and contextualist answers to the challenge of the external world sceptic represent a "significant step forward" in the vindication of our epistemic achievements, insofar as they make it possible to reconcile the claim that we possess much ordinary knowledge about our surroundings with the concession that we lack knowledge of such anti-sceptical propositions as that we are not being massively deceived by an evil demon or a team of malevolent super-psychologists. However, far from being satisfied with such a conciliatory outcome, Alai goes on to face the sceptic's challenge head-on, carefully crafting an explanationist strategy aimed at showing that we are justified to believe to a degree that is adequate for knowledge even such anti-sceptical propositions. In this paper, I do not discuss his attempt to provide a probabilistic vindication of the anti-sceptical use of Inference to the Best Explanation, nor do I pause to evaluate the prospects for explanationist strategies generally, focussing instead on some structural aspects of Alai's proposal. I discuss the relationship between conciliatory and explanationist anti-sceptical strategies, relate them to different accounts of the structure of epistemic justification, and explore the options that an explanationist can take on the issue of the deductive closure of knowledge and epistemic justification.