 Prima facie, ‘Every old patient respects some doctor’ and ‘Some young politician likes every liar’ exhibit common modes of linguistic combination. So a natural hypothesis is that the meaning of each sentence is fixed by these modes of combination, given the relevant word meanings. It may be hard to see how this hypothesis could be true if there are widespread mismatches between logical and grammatical form. But it is also hard to see how the hypothesis could be false. Children, who have finite cognitive resources, typically acquire the capacity to understand the endlessly many expressions of the languages spoken around them. A great deal of recent work has focussed on these issues, concerning the connections between logical form and the senses in which natural languages are semantically  compositional.