 First we should notice Aristotle’s solution. Aristotle is in no doubt that not everything that happens, happens of necessity. He accepts indeed (19a23–5) that “What is, necessarily is, when it is; and what is not, necessarily is not, when it is not.” But he goes on to say, “But not everything that is, necessarily is; and not everything that is not, necessarily is not.” So what is his solution? Here it must be said that there is more than one view (Aristotle, Categories and De Interpretatione, 137–42). On one view he rejects the move from truth to necessity. That may indeed be the right move to make, but in what follows I shall take it that Aristotle actually offers a different solution, which, rightly or wrongly, I shall refer to as “the Aristotelian solution”. On this view his solution is to deny that it is necessary that the affirmation or the negation is true or false when this relates to things that do not happen of necessity. That is to say, his solution is that neither what the first person said in 1900 (“There will be a sea-battle on 1/1/2100.”) nor what the second person said (“There will not be a sea-battle on 1/1/2100.”) was true. What each person said was in fact neither true nor false. So we may represent the Aristotelian solution as one which rejects the law of bivalence: