In the thread below on knowing who, David Braun suggests that statements like the following sound contradictory.

bq. ‘Zaphod Beeblebrox *kissed* that guy’ is an answer to the question ‘Who did Zaphod Beeblebrox kiss?’, and B knows that Zaphod Beeblebrox kissed that guy, and so she knows an answer to the question of who Zaphod Beeblebrox kissed, but she does not know who Zaphod Beeblebrox kissed.

I think this sounds fine in some cases, or at least if it doesn’t this tells us something about what counts as an answer to a question.

Let’s get some background. As President of the galaxy, Zaphod legalised gay marriage, so ‘that guy’ denotes in the context his husband. Last night Zaphod was at a party where by all accounts he kissed celebrities from every major star system. He also gave that guy a goodnight kiss. The identities of the celebrities are a mystery. B knows that Zaphod kissed his husband, but not the mysterious celebrities.

Now what about David’s sentence? I think B doesn’t know who Zaphod kissed. She does know that he kissed that guy. Is ‘Zaphod kissed that guy’ _an_ answer to the question of who Zaphod kissed? I’m half-tempted to say it is, so here’s a case where David’s ‘contradictory’ sounding sentence is true. But maybe I’m missing something crucial about the semantics of plurals and/or questions here.