What is grammar? Why does it exist? What difference, if any, does it make to the organization of meaning? This book seeks to give principled answers to these questions. Its topic is 'universal' grammar, in the sense that grammar is universal to human populations. But while modern generative grammar stands in the tradition of 'Cartesian linguistics' as emerging in the 17th century, this book re-addresses the question of the grammatical in a broader historical frame, taking inspiration from Modistic and Ancient Indian philosopher-linguists to formulate a different and 'Un-Cartesian' programme...