The Magic Number 4: Evolutionary Pressures on Semantic Frame Structure

We propose that the “magic number 4” puzzle of argument structure in semantic frames across most human languages is explained by selection pressures given inherent computational efficiency properties naturally arising from fundamental combinatorial mathematics of compositionality. Irrespective of language, school, or theoretical bias, linguists have long observed that what are now generally called “semantic frames” empirically bear a maximum limit of four core arguments per frame, for unknown reasons. We explain how this limit would automatically emerge as a consequence of evolutionary preference for the formal equivalence class of inversion transductions as an optimal balance between expressivity and fast tractable polynomial-time language learning and interpretation/transduction between different representation languages.