Hard and soft conditions on the Faculty of Language: constituting parametric variation

In this paper, I argue that both parametric variation and the alleged differences between languages in terms of their internal complexity straightforwardly follow from the Strongest Minimalist Thesis that takes the Faculty of Language to be an optimal solution to conditions that neighboring mental modules impose on it. Hard conditions like legibility at the linguistic interfaces invoke simplicity metrics that, given that they stem from different mental modules, are not harmonious. Widely attested expression strategies, such as agreement or movement, are a direct result of conflicting simplicity metrics, so that UG, perceived as a toolbox that shapes natural language, can be taken to consist of a limited number of marking strategies, all resulting from conflicting simplicity metrics. As such, the contents of UG follow from simplicity requirements, and therefore no longer necessitate linguistic principles, valued or unvalued, to be innately present. Finally, I show that the Strongest Minimalist Thesis does not require that languages themselves have to be optimal in connecting sound to meaning.