Full Idea
The fact that speakers of natural languages have the capacity to understand indefinitely many new sentences suggests that meaning must be compositional.
Gist of Idea
Understanding unlimited numbers of sentences suggests that meaning is compositional
Source
Ofra Magidor (Category Mistakes [2013], 3.2.1)
Book Reference
Magidor,Ofra: 'Category Mistakes' [OUP 2013], p.46
A Reaction
To some extent, the compositionality of meaning is so obvious as to hardly require pointing out. It is the precise nature of the claim, and the extent to which whole sentences can add to the compositional meaning, that is of interest.