|Actualism: in relation to worlds the thesis that only our own world is real. - Counter-position essentialism.|
Books on Amazon
Actualism / Stalnaker: does not take possible worlds literally as worlds - but as ways of how the world might have been - punch line: contingent identity is not allowed, but probably contingent dissimilarity.
Actualism / Stalnaker: is no restrictive metaphysical theory as materialism or nominalism - it is just a trivial consequence of the meaning of "actual".
Presentism / Stalnaker: analogous to actualism regarding worlds: thesis, we are extended in time just as we are spread over possible worlds - then we can have real temporal identity. (Stalnaker per) - fusion / fission / personal identity: are then cases where persons who were separated earlier become identical or a person is divided into two.
Ways a World may be Oxford New York 2003