Generative semantics was a research program in theoretical linguistics which held that syntactic structures are computed on the basis of meanings rather than the other way around.
Its proponents included Haj Ross, Paul Postal, James McCawley, and George Lakoff, who dubbed themselves "The Four Horsemen of the Apocalypse".
In the 1960s, work in the generative tradition assumed that semantics was interpretive in the sense that the meaning of a sentence was computed on the basis of its syntactic structure rather than the other way around.
[1] Generative semanticists wanted to account for all cases of synonymity in a similar fashion, which proved to be a challenge given the tools available at the time.
By contrast, generative semantics was faced with the problem of explaining the emergence of meaning in neuro-biological rather than social and rational terms.
Thus, engaging with the physical world provides the person with visual, tactile and other sensory input, which crystallizes into language in the form of conceptual metaphors, organizing rational thinking.