 A common complaint against Supp’s theory is that if conditionals do not express propositions with truth conditions, we have no account of the behaviour of compound sentences with conditionals as parts (see e.g. Lewis (1976, p. 142)). Probability theory is no help: conditional probabilities never occur inside wider constructions. However, no theory has an intuitively adequate account of compounds of conditionals: we saw in §2.4 that there are compounds which Hook gets wrong; and compounds which Arrow gets wrong. Grice’s and Jackson’s defences of Hook focus on what more is needed to justify the assertion of a conditional, beyond belief that it is true. This is no help when it occurs, unasserted, as a constituent of a longer sentence, as Jackson accepts. And with negations of conditionals and conditionals in antecedents, we saw, the problem is reversed: we assert conditionals which we would not believe if we construed them truth-functionally.