Could Cleopatra Have Been Male?
Kripke surely said something important in arguing that we don’t “discover” possible worlds as if examining through a telescope various actors on a distant planet. (Metaphysics: An Anthology, 78) Instead, possible worlds are posited, stipulated, conceived, and ultimately created in one’s imagination. Our dealings with possible worlds are games. Consider reading fiction or playing a game like World of Warcraft. You say: I am playing the role of such and such class, e.g., a mage. If you get tired of playing a mage, you delete the character and create another, say, warrior, and say that in the Warcraft universe you are that. Nothing unites you and the character: the Warcraft world is about as far away from the real world as a world could possibly be.
On Kripke’s theory we could simply stipulate that in a possible world I am currently considering that fat male sailor is Cleopatra. The possible worlds are ours to play with. But, someone who worries about trans-world identity might object: really, what would that accomplish? We have to figure out when identity is preserved through change and when it is not. What we are dealing with, then, is a perturbation problem: How much can we muck around with Cleopatra’s character before it would no longer be reasonable to call her by her actual-world name?
The main question regarding trans-world identity is, Which of your properties are essential and which are accidental to you? If is clear that Cleopatra can’t be a musical performance, because it is her essence to be human. The name Cleopatra is a rigid designator vis-a-vis her humanity: it picks out a human being in all possible worlds in which Cleopatra exists. On the other hand, it is probably not her essence to be blond, though who knows: if she had not been blonde, Mark Anthony might not have taken a liking to her. But what of a property like being female? I think that between essential and accidental properties we must situate something called “proper accidents.” A proper accident is not officially part of the essence of a thing, but it follows from its essence, such that to remove it would change the thing into a monster. One standard example is the capacity of laughing: a human being is not defined by it, but a creature who is incapable of laughter would scarcely be human. Cleopatra’s being female would seem to be her proper accident; it is arguable that she would be unrecognizable if she were put into the body of a male.
Thus, as Robert M. Adams puts it, we must engage in both “conceptual legislation” and “metaphysical discovery.” (182)