  Reflection on examples drawn from more homely contexts also casts doubt on the idea that all genuine evidence is in principle accessible to multiple individuals. When one has a headache, one is typically justified in believing that one has a headache. While others might have evidence that one has a headache—evidence afforded, perhaps, by one's testimony, or by one's non-linguistic behavior—it is implausible that whatever evidence others possess is identical with that which justifies one's own belief that one has a headache. Indeed, it seems dubious that others could have one's evidence, given that others cannot literally share one's headache. 