 Secondly, if a person microphysically identical with me, located in an identical environment (both present and past), can lack any phenomenal experiences, then facts pertaining to experience and feeling, facts about qualia, are not necessarily fixed or determined by the objective microphysical facts. And this the physicalist cannot allow, even if she concedes that phenomenally conscious states are not strictly identical with internal, objective, physical states. For the physicalist, whatever her stripe, must at least believe that the microphysical facts determine all the facts, that any world that was exactly like ours in all microphysical respects (down to the smallest detail, to the position of every single boson, for example) would have to be like our world in all respects (having identical mountains, lakes, glaciers, trees, rocks, sentient creatures, cities, and so on).