But if knowledge is intrinsically valuable, then this is very bad—such that Joan of Arc’s burning at the stake would be a good thing.
The world where Joan of Arc died at the stake and people truthfully believe it is not one step away from the world where she didn’t die at the stake and people falsely believe it.
Naively, you can say “the worlds are different with regards to the fate of Joan of Arc, but they are otherwise identical because people have the same beliefs in both of them.” But that’s not actually true. People have similar-looking beliefs in both worlds, but the process by which they achieved them is different. Claiming that both worlds are identical aside from Joan’s fate is equivalent to saying “the method by which you came by your beliefs doesn’t matter”.
That just moves the problem back one step. The processes that lead to the evidence in the untruth universe can’t be the same as the ones which lead to the similar-looking evidence in the truth universe (unless you get Gettiered, and then the people in the truth universe don’t actually have knowledge.) So if you don’t ignore history, the worlds still differ in ways other than just the fate of Joan.
The world where Joan of Arc died at the stake and people truthfully believe it is not one step away from the world where she didn’t die at the stake and people falsely believe it.
Naively, you can say “the worlds are different with regards to the fate of Joan of Arc, but they are otherwise identical because people have the same beliefs in both of them.” But that’s not actually true. People have similar-looking beliefs in both worlds, but the process by which they achieved them is different. Claiming that both worlds are identical aside from Joan’s fate is equivalent to saying “the method by which you came by your beliefs doesn’t matter”.
We are stipulating that we would have the same evidence in both cases, so it would lead to the same beliefs, just with different truth values.
That just moves the problem back one step. The processes that lead to the evidence in the untruth universe can’t be the same as the ones which lead to the similar-looking evidence in the truth universe (unless you get Gettiered, and then the people in the truth universe don’t actually have knowledge.) So if you don’t ignore history, the worlds still differ in ways other than just the fate of Joan.