Let us return, then, to Quine's favored formulation of the criterion involving the ‘must’ and explore whether it is compatible with an extensionalist account. Indeed, ordinary uses of ‘must’ and other modals are often used to signal generality without making the content of what is asserted modal. Consider the following example: “A set of five numbers between 1 and 9, inclusive, must contain at least one odd number”. The content is simply that every set of five numbers between 1 and 9, inclusive contains at least one odd number. (Perhaps the ‘must’ is also epistemic, but not in a way that affects the content of what is asserted.)  Similarly, Quine's criterion can be interpreted as innocent quantification: 