 Many early ethicists of belief modeled their accounts on deontological ethical theories that tend to formulate principles synchronically. Recently, however, virtue epistemologists have emphasized what they take to be the diachronic character of our fundamental doxastic obligations, and suggest that synchronic principles requiring sufficient evidence for a belief at a time are plausibly viewed as underwritten by more fundamental diachronic principles enjoining the cultivation of virtuous intellectual character (Zagzebski 1996, Roberts and Wood 2007, Sosa 2007, Audi 2008b).