To address the paradox: If I show you a box and (trustworthily) tell you that there’s one object in the box, and then you look through a tiny hole in the box so all you can see is the color, and you see not-black, that is probably evidence that not all ravens are black (unless we think there’s way more non-black objects in worlds where all ravens are black, enough to overcome the possibility that we’re looking at a non-black raven). Then, if we open the box and see a non-raven, that observation is evidence in favor of “all ravens are black”, because we’ve (mostly) screened off the evidence against—we definitely weren’t looking at a nonblack raven.
To address the paradox: If I show you a box and (trustworthily) tell you that there’s one object in the box, and then you look through a tiny hole in the box so all you can see is the color, and you see not-black, that is probably evidence that not all ravens are black (unless we think there’s way more non-black objects in worlds where all ravens are black, enough to overcome the possibility that we’re looking at a non-black raven). Then, if we open the box and see a non-raven, that observation is evidence in favor of “all ravens are black”, because we’ve (mostly) screened off the evidence against—we definitely weren’t looking at a nonblack raven.