Just common sense, really. Something biblical inerrantists are woefully lacking in:
When you lack evidence, the only way to decide whether or not to believe something is to ask: Is it likely? If you tell me a bird flew past my window, I will probably believe you, even though I did not see it myself and I have no evidence. That is because such a thing is likely. I have seen it happen before. It is more likely that a bird flew past my window, than that you are deceiving me. But if you tell me a pig flew past my window, I will not believe you, because my past experience tells me that such things do not happen, and so I presume that what you reported is false. Thus, where there is no evidence we have to rely on our own past experience of the sort of things that really happen ( Carl Lofmark from What Is The Bible, pp. 41-42).