 There is a clear difference between (4) and (5)—the first one is unproblematic, the second markedly odd. This difference is plausibly a matter of meaning, and so (4) and (5) cannot be synonyms. Nonetheless, the first sentences are at least truth-conditionally equivalent. If we adopt a conception of meaning where truth-conditional equivalence is sufficient for synonymy, we have an apparent counterexample to compositionality.