Full Idea
The principle that if a competent speaker understands some terms then they understand a sentence made up of them entails that category mistakes are meaningful (as in understanding 'the number two' and 'is green').
Gist of Idea
The normal compositional view makes category mistakes meaningful
Source
Ofra Magidor (Category Mistakes [2013], 3.2.1)
Book Reference
Magidor,Ofra: 'Category Mistakes' [OUP 2013], p.47
A Reaction
[compressed version] It is normal to impose restrictions on plausible compositionality, and thus back away from this claim, but I rather sympathise with it. She adds to a second version of the principle the proviso 'IF the sentence is meaningful'.