The Planets are Nine in Number

W. V. Quine had, in Word and Object, drawn prominent attention to the opacity of the necessity operator, by comparing the sentences(1) Necessarily 9 > 4and(2) Necessarily the number of major planets > 4.Of these, Quine had said, “surely, on any plausible interpretation, (1) is true and (2) is false. Since 9 = the number of major planets, we can conclude that the position of ‘9’ in (1) is not purely referential and hence that the necessity operator is opaque.” The puzzle has generated a good deal of interest, particularly with an eye to the prospects of quantifying in modal contexts. But, given the substantial literature that has sprung up around the issue, it is rather easy to misunderstand the force of any challenge to Quine's account.