 Though these and other developments in logic are interesting in their own right, the Stoic treatment of certain problems about modality and bivalence are more significant for the shape of Stoicism as a whole. Chrysippus in particular was convinced that bivalence and the law of excluded middle apply even to contingent statements about particular future events or states of affairs. (The law of excluded middle says that for a proposition, p, and its contradictory, not-p, ‘(p or not-p)’ is necessarily true, while bivalence insists that the truth table that defines a connective like ‘or’ contains only two values, true and false.) Aristotle’s discussion in chapter 9 of On Interpretation of a hypothetical sea battle which either will or will not happen tomorrow has traditionally been taken to deny this. (The proper interpretation of Aristotle’s position is in fact disputed by scholars, but that need not concern us here.) Aristotle had presented an argument that if it is either true or false now that there will be a sea battle tomorrow (and let us suppose for the sake of argument that it is false), then our present deliberation about whether we should go out and fight tomorrow would be pointless. After all, if it is already true now that there will be no battle, then whatever we decide, we won’t fight. This kind of reasoning seems to pose a threat to the meaningfulness of deliberation and it is reasoning that proceeds simply from considerations about the nature of propositions and their truth or falsity. The Stoic Chrysippus seems to have connected this logically-motivated pathway to fatalism with the question of causal determinism (Cicero, 38G). He insisted that if there was motion without a cause, it would mean that some propositions would not be either true or false. But in fact, every proposition is either true or false. So he concluded that there is no motion without a cause. 