A bolt of lightning creates your perfect physical copy — does it mean anything you say?
Philosopher Donald Davidson imagined lightning striking a swamp and, by sheer chance, rearranging molecules into an exact physical duplicate of himself — same brain, same movements, even greeting his friends by name. Davidson argued this 'Swampman' couldn't really mean anything by those words, since its brain states have no causal history connecting them to the things they seem to refer to. Meaning, he argued, depends on causal history, not just current physical state.