Syntactic computations, the cartography of syntactic structures, and “further explanation” in syntax

Leçon de clôture de la Chaire Internationale de Recherche Blaise Pascal financée par l'Etat et la Région d'Ile-de-France, gérée par la Fondation de l'Ecole Normale Supérieure. 

Abstract
The main objective of this talk is to illustrate the cartography of syntactic structures, a line of inquiry which has a wide descriptive dimension, and significant implications for syntactic theory and the study of the interfaces with sound and meaning. I would like to start by briefly illustrating the basic ingredients of syntactic computation, first and foremost Merge, the fundamental structure-building operation, and its capacity to generate hierarchical structures. Merge is an extremely simple operation (“take two elements and string them together to form a third element”), but its recursive applications on a rich functional and substantive lexicon quickly produce hierarchical configurations of great complexity. The cartography of syntactic structures is the program which aims at drawing realistic maps of syntactic configurations, maps which do justice to the inherent complexity of such objects. The cartographic projects have been steadily extending their empirical scope over the last fifteen years, and have offered an important new tool for comparative linguistics, as well as for the study of the interfaces with representations of sound and meaning. Here, I will briefly illustrate some of the results of cartographic analysis, with special reference to the work on the initial periphery of the clause and its impact on the study of the informational structure and, more generally, of properties of “scope-discourse” semantics. 

In the third part, I would like to address the issue of the “further explanation” of cartographic properties. Syntactic maps express rich descriptive properties such as fixed subsequences, exclusion patterns, the “halting problem” for movement (when certain positions in the map are reached, movement must necessarily continue, while other positions trigger freezing effects and movement must stop), and the like. It is very unlikely that such properties may be primitive ingredients of the human language faculty. A more plausible tack is to try to trace the rich descriptive outcome of cartographic studies to a deeper explanation in terms of fundamental principles of linguistic computations. In this final part, I will illustrate the role of principles operating at the interface with meaning, and of formal principles of labeling and locality in the explanatory endeavor which is prompted by cartographic results.