 (Here his analogy with “but” etc. fails. “But” can occur in unasserted clauses: “Either he arrived on time but didn’t wait for us, or he never arrived at all” (see Woods (1997, p. 61)). It also occurs in questions and commands: “Shut the door but leave the window open”. “Does anyone want eggs but no ham?”. “But” means “and in contrast”. Its meaning is not given by an “assertability condition”.)