How did Chomsky’s ideas lead philosophers to study rules that assign meanings to sentences?

Noam Chomsky’s work in the 1950s, particularly his book Syntactic Structures, fundamentally shifted the study of language by arguing that natural languages are characterized by "indefinite extensibility". Chomsky demonstrated that language learners acquire the ability to recognize the grammaticality of an infinite number of sentences despite being exposed to only a finite, often defective, sample of speech.1

This "poverty of the stimulus" argument led to the conclusion that mastery of a language entails internalizing a system of rules for generating these sentences. Philosophers enthusiastically endorsed the idea that natural languages are syntactically rule-governed, and they observed that language learners also acquire the ability to recognize the meaningfulness of an infinite number of sentences. This skill implies the existence of a set of rules for assigning meanings to utterances, which inaugurated a second "golden age" of formal studies in philosophical semantics.1

Consequently, the focus shifted toward investigating the nature of these rules, leading to various developments such as "possible world semantics" and truth-conditional theories of meaning, which attempt to formalize how speakers derive meaning from the structure of language.12