Are indefinite descriptions ambiguous?

Perhaps most philosophers would agree that 'a(n)' and 'some' at least sometimes function as existential quantifiers. This position entails that at least some occurrences of sentences such as: A man is in the next room. or Some man is in the next room. are true just in case at least one thing is a man and is in the next room. What is not as widely agreed upon is whether 'a(n)' and 'some' always serve to assert existential generalization. Let us call the view that 'a(n)' and 'some' are univocal and do always have this semantic function the univocality thesis (UT)) In recent years, UT has come under attack. The dissenters have generally held that in addition to asserting existential generalization, 'a(n)' and 'some' exhibit some other semantic function. Though not always agreeing on what the other semantic function is, these opponents of UT hold that 'a(n)' and 'some' are ambiguous between an existential quantifier reading and this other reading. Let us call the view that 'a(n)' and 'some' are ambiguous in this way the ambiguity thesis (AT), while bearing in mind that those who hold the theory may differ on the analysis of the non-quantifier reading they attribute to 'a(n)' and 'some'. 2 The purpose of the present essay is to critically examine some of the arguments that have appeared in the literature for AT over UT. I intend to argue that the proponents of UT can meet the objections raised by those endorsing AT. 3 I shall discuss only the indefinite article 'a(n)', though the remarks I shall make apply equally well to 'some', (henceforth phrases of the form 'a(n) F' shall be called indefinites).