Lewis tried to use his analysis of subjunctive conditionals to explain time's arrow: our sense of the fixity of the past and non-fixity of the future. This required him to state his analysis—and thus his conditions for closeness of worlds—without using any temporal-order concepts, only temporal-metric ones. Criticism of his ingenious attempt to do this, especially his thesis about what it takes for there to be a convergence of two previously unalike worlds.
Keywords: conditionals, convergence, fixity, future, Lewis, past, possible worlds, subjunctive conditionals, time, time's arrow