Adrian Miroiu WORLDS WITHIN WORLDS

It is sometimes argued that possible worlds are too rich. Indeed, for every sentence φ and every world w, either φ is true at w, or ¬φ is true at w. Possible worlds leave nothing unsettled: for any question one may ask, there is always an answer, yes or no. My view goes along the opposite side. I take possible worlds to be incredibly poor, and I think that a good deal can be added to them. The claim I want to defend is that this can be done by taking into account the extremely large class of world-indexed sentences. Let φ be some sentence. Then a hoard of world-indexed new sentences can be produced. From “Quine is a distinguished philosopher” we get the sentence: “Actually Quine is a distinguished philosopher”, and also the sentence: “At world w Quine is a distinguished philosopher”, for any w. On the standard account, a sentence is true or false at every possible world. Thus, the sentence “Quine is a distinguished philosopher” is true at a world w if at w it holds that Quine is a distinguished philosopher, and false otherwise. Now, what about the sentence “Actually Quine is a distinguished philosopher”? For any world w, it is true at w if it holds at the actual world that Quine is a distinguished philosopher, and false otherwise. Next, how can we establish the truth value at world w′ of the sentence “At world w Quine is a distinguished philosopher”? The issue we face is how to handle the condition that at w′ it holds that Quine is a distinguished philosopher at w. The standard move looks to be something like this. Suppose that at w it is indeed the case that Quine is a distinguished philosopher, i.e. at w the truth-value of the sentence “Quine is a distinguished philosopher” is truth. Now, this is a condition that cannot fail to obtain: while it is of course possible to hold that at some world w′′ Quine is not a distinguished philosopher, there is no way to deny that he is so at w. Hence at every world w the sen-