Most intuition checks in epistemology involve made-up cases rather than found cases. The lottery cases may be an exception, but I think we should have a few more. Here’s my current favourite.

Consider Hamlet as he stands at “the end of Act I”:http://the-tech.mit.edu/Shakespeare/hamlet/hamlet.1.5.html. Does he know, or if you like _know_, that his uncle murdered his father? Let’s review the case for and against.

On the pro side, he has testimonial evidence, and the provider of the testimony presumably has first-hand evidence of the murderous act. So there’s a causal chain from the act leading to Hamlet. And that should usually do.

On the other hand, and it’s a big other hand, it’s a ghost. This is not the standard kind of testimony we’re talking about.

There are a couple of textual points that seem relevant. Hamlet seems at least a little familiar with ghosts, which might matter if one thinks, for instance, that internal justification of the evidence matters. On the other hand, it isn’t really made clear in the text just _how_ the King knows how he was murdered. As he says,

bq. Thus was I, sleeping, by a brother’s hand
Of life, of crown, of queen, at once dispatch’d:

So maybe the causal chain here doesn’t stretch straight back to the actual killing, but to when (in the afterlife?) the King found out about his method of murder. So it’s all a bit messy.

And if one is a two-dimensionalist about justification it will turn out that Hamlet clearly does not have a justified belief, because lectures from ghosts are not _actually_ a reliable source of evidence.

There’s a Williamsonian point coming behind all this. Possibly it’s a little hard to say whether Hamlet knows at the end of Act I whether his uncle murdered his father. Perhaps he does, perhaps he doesn’t. But the question of whether he does or not is not a distinctively philosophical question, nor even a distinctively _conceptual_ question. We’re just asking what the state of play is at that stage of the story. It’s just the same kind of question as if we ask whether Laertes knows at the end of act IV that Hamlet killed _his_ father. (Yes, I think, though I can sort of imagine an argument to the contrary, what with Claudius having a vested interest in having Laertes come to believe it was Hamlet.) There’s no _generalised_ ground for scepticism about the judgement about Hamlet that doesn’t extend to scepticism about the judgement about Laertes. And that seems preposterous – very often we know exactly what characters in plays do and don’t know. Someone who wants to argue that we _could not_ know, or even have justified beliefs about, whether Hamlet knows how his father died at the end of Act I has to appeal, in some way or other, to facts particular to the case. That’s not a lesson I’ve always followed in the past, and it undermines some of my pro-JTB arguments.