Structurally De ned Alternatives and Lexicalizations of XOR

In his recent paper on the symmetry problem Roni Katzir argues that “the only relevant factor” for the calculation of any Quantity implicature “is structure” (, ). My rst aim here is to refute Katzir by providing three examples that show that structural complexity is irrelevant to the calculation of some Quantity implicatures. My second aim is to cast doubt on the advisability of assuming—as Katzir and others in effect do—that exactly one factor is relevant to the calculation of any Quantity implicature. To discover that there is exactly one such factor would be a major advance in our understanding of implicature. But at this stage it’s simply an unwarranted assumption. Although (-a) conversationally implicates (-b), (-a) does not implicate (-c).