Laurence BonJour's (1985) coherence theory of empirical knowledge relies heavily on a traditional foundationalist theory of a priori knowledge. He argues that a foundationalist, rationalist theory of a priori justification is indispensable for a coherence theory. BonJour (1998) continues this theme, arguing that a traditional account of a priori justification is indispensable for the justification of putative a priori truths, the justification of any non-observational belief and the justification of reasoning itself. While BonJour's indispensability arguments have received some critical discussion (Gendler 2001; Harman 2001; Beebe 2008), no one has investigated the indispensability arguments from a coherentist perspective. This perspective offers a fruitful take on BonJour's arguments, because he does not appreciate the depth of the coherentist alternative to the traditional empiricist-rationalist debate. This is surprising on account of BonJour's previous defense of coherentism. Two significant conclusions emerge: first, BonJour's indispensability arguments beg central questions about an explanationist form of coherentism; second, BonJour's original defense of coherentism took on board certain assumptions that inevitably led to the demise of his form of coherentism. The positive conclusion of this article is that explanatory coherentism is more coherent than BonJour's indispensability arguments assume, and more coherent than BonJour's earlier coherentist epistemology.