 Most of us also believe that things, as a whole, needn't have been  just as they are. Rather, things might have been different in  countless ways, both trivial and profound. History, from the very  beginning, could have unfolded quite other than it did in fact: the  matter constituting a distant star might never have organized well  enough to give light; species that survived might just as well have  died off; battles won might have been lost; children born might never have been conceived and children never conceived might otherwise have been born. In any case, no matter how things had gone they would  still have been part of a single, maximally inclusive,  all-encompassing situation, a single world. Intuitively, then, the  actual world of which Anne's immediate situation is a part is only  one among many possible worlds. 