“Most similar” is key. There may be some “possible worlds” in which his headache did not go away—for example, a world in which he took the aspirin and then bumped his head on the bathroom door. But that world contains an extra, adventitious circumstance.
so this ability really depends on the ability to disentangle various phemonema!?!?
this seems important!?!
if headache/bang head were not separate concepts then we would not be able to do this!?
