It occurred to me today that the presumption of consistency is epistemically more modest than inconsistency. For example, suppose one holds two beliefs, A and B, which are both believed to be true by some subject (let’s call her Susie) not because she has analyzed the consistency of A and B, but because nobody has demonstrated to her that there is any inconsistency between A and B. Now, perhaps she’s never even thought very much about A and B both being true. Somebody else might object to her holding both beliefs, and argue that A seems to imply ~B (and/or vice versa). Now, so long as A does not logically entail ~B, there is no explicit inconsistency, but perhaps they seem incompatible because of hidden assumptions. For instance, suppose A were “on July 17, 2009, I stayed home all day and played video games in my room in Canada”, and B were “on July 17, 2009, I was in Japan” – there would be no explicit contradiction, but A would seem to imply ~B (because we presuppose that bilocation is either not possible or at least not very plausible, or else that time travel is unlikely or impossible, or else that… – and the list goes on).
Supposing the objector to Susie’s holding some belief A, and some belief B, (suppose, for the sake of argument, that A is actually “the Eucharist involves the transubstantiation of bread and wine into Christ” and B is actually “tables, chairs and other such objects are mereological sums which have no ‘substance’ or substantial form”. While an objector might point out to Susie that these beliefs seem odd bedfellows, and Susie has never thought about this apparent inconsistency before, she finds she wants to retain both beliefs A and B. The objector might ask Susie to account for how both could be true, and suggest that if Susie cannot provide a story for how both A and B are true, she should then abandon one or both of those beliefs.
However, since inconsistency is so hard to demonstrate, and since things are, prima facie, more likely to be logically consistent than logically inconsistent, I think perhaps the burden of proof should be on Susie’s objector to demonstrate some real incompatibility between A and B. Unless and until the objector does so, Susie is, it seems, plausibly within her epistemic rights to retain both beliefs A and B (presumably she has good reasons for either belief). Thus, since people hold a variety of beliefs (50,000 for the average adult, give or take) and since guaranteeing maximal consistency is impossible to demand from a human cognizer, it seems that the epistemic attitude of a person should be that, if she has good reasons to accept some belief A, and good reasons to accept some belief B, even if she cannot provide a story for how both are true, she is well within her rights to retain both beliefs unless and until an objector can demonstrate incompatibility or inconsistency.