I am writing a short essay for philosophy of langauge arguing the shortcoming of rigid designation in identifying the same entity in all possible worlds. I would like criticism of my thought experiment. Below is what I have so far:
Will the Real Nixon Please Stand Up?
Recall, that one of the crucial problems with the descriptivist account of proper names is that if a name is identical to a description, then in all worlds in which a person exists, he must have that description. This is a matter of necessity due to the nature of identity. If “Richard Nixon†is identical with “the only president of the United States to resign,†then there can be no possible world in Nixon did not resign. Clearly, however, we can imagine scenarios in which Nixon did not resign. Maybe Watergate was successfully executed and he had no reason to resign. Maybe he stayed in office, fought the impeachment procedures, and was removed from office by the Senate. Whatever the differences are, we usually won’t see it as necessary that Richard Nixon was the first president to resign. As a result, we need a new theory of proper names, and Kripke introduces the causal theory. How we are able to go from the causal connections in one world to a possible world in which they do not exist, however, is a bit of a mystery. There is no trouble identifying Nixon in a possible world where he works at an ice cream shop or at Best Buy, but what if we stretch circumstances a bit where singular identification becomes impossible?
Holding the common sense approach to identity, which Kripke takes, rather than a deeper philosophical one, there is no denying that throughout his life, Richard Nixon was always identifiable by his proper name. Given that proper names attach to the same entity regardless of a change in properties, then there is a possible world in which Richard Nixon was a bartender for the whole of his adult life. Nothing is problematic until we raise the possibility of both entities being in the same world. It is possible that the Nixon as we know him had a twin brother who lived a rather mundane life as a bartender, but there is also another world in which Nixon lived an almost identical life to that of his possible twin and was physically identical to him in all ways from DNA up. Ignoring the world in which Nixon has a twin bother as a bartender and focusing on our world and the world in which Nixon is a bartender, we would agree that both fit the rigid designation of “Richard Nixon.†Nixon as a bartender is just the type of counterfactual situation in which descriptivism fails and the causal theory succeeds. When both are placed in the same world, however, we run into serious trouble, especially keeping in mind that descriptions need to be avoided. We are inclined to say that the president is Nixon and the bartender is his twin, but at the same time, we have agreed that there is a world in which there is an entity who is rigidly designated by the proper name “Richard Nixon†and who is identical to Nixon’s twins in the world in which Nixon is president.