 The following paradox — perhaps the ultimate paradox of identity — derives from an argument of Church (1982). Suppose Pierre thinks that London and Londres are different cities, but of course doesn’t think that London is different from London, or that Londres is different from Londres. Assuming that proper names lack Fregean senses, we can apply LL to get the result that London and Londres are distinct. We have here an argument that, given the standard account of identity, merely thinking that \(x\) and \(y\) are distinct is enough to make them so. There are, of course, a number of ways around this conclusion without abandoning the standard account of identity. Church himself saw the argument (his version of it) as demonstrating the inadequacy of Russellian intensional logic — in which variables and constants operate as they do in extensional logic, i.e., unequipped with senses. (For another reaction, see Salmon 1986.) But there are strong arguments against the view that names (or variables) have senses (Kripke 1980). In light of these arguments, Church’s argument may be viewed as posing yet another paradox of identity.