Vice epistemology is the philosophical study of the nature, identity, and epistemological significance of intellectual vices. Such vices include gullibility, dogmatism, prejudice, closed-mindedness, and negligence. These are intellectual character vices, that is, intellectual vices that are also character traits. I ask how the notion of an intellectual character vice should be understood, whether such vices exist, and how they might be epistemologically significant. The proposal is that intellectual character vices are intellectual character traits that impede effective and responsible inquiry. I (...) argue that situationist critiques of virtue epistemology pose no significant threat to this proposal. Studies by social psychologists of belief in conspiracy theories suggest that it is sometimes appropriate to explain questionable beliefs by reference to intellectual character vices. Neither ‘regulative’ nor ‘analytic’ epistemology has any good reason to question the epistemological significance of such vices. (shrink)