This paper presents evidence that semantic notions-such as presupposition, speaker's and hearer's beliefs about the world, and previous discourse-must be taken into account in a complete treatment of the distribution of some and any in conditional, negative, and interrogative sentences. Syntactic conditions alone will not account for the fact that, in certain sentence types, the two forms occur with different meanings. In his article on negation in English, Klima (1964) proposed a rule that has been accepted more or less unquestioningly into the pantheon of known transformational rules of English syntax. This rule was called 'Indefinite incorporation': it took structures containing a form of the quantifier some and, obligatorily in certain specified environments (particularly in negatives and questions), turned these instances of some to any; (1) [NEG]PVP X - QUANT = neg - X - INDEF + QUANT INDEF + QUAvNT was later rewritten as any. This was the earliest and fullest discussion in transformational grammar of the alternations found in English between these quantifiers, and was the first transformational treatment of the differences in quantification in some-environments and in any-environments. Later work has extended the knowledge of those environments in which any is found: they are summarized in 2. Note that the asterisks are put in according to Klima's formulation.