Les limites de la performativité des énoncés économiques: les apports de John Searle

The problematic of performativity has recently produced several criticisms and debates about the status of the economic discourse. Indeed the affirmation that economist shapes the world by describing it could leads to the subjectivist idea that each theory can in fine be 'true' and each theory can perform the social world in his specific way. This work clarifies this problematic in connecting it with the institutional theory of John Searle. We define performativity as a particular type of assignment of function. Finally, this enables us to show that performativity is limited by two kinds of factors : brut facts and social facts.

Proto-South-East Asia as a trigger of early angiosperm diversification

Darwin described as an 'abominable mystery' the abrupt origin of angiosperms in the mid-Cretaceous and the high diversification rates in their early history. The father of evolutionary theory could not fathom this rapid diversification and rather invoked that 'there was during long ages a small isolated continent in the S. hemisphere, which served as the birthplace of the higher plants'. In this essay, we comment on the spatial origin of angiosperms, but focus primarily on understanding the abiotic factors that promoted the early diversification of angiosperms by reviewing palaeobotanical, palaeogeographical, phylogenetics and biogeographical evidence. We argue that islands located in the region today occupied by South-East Asia played a major role in angiosperm diversification during the Late Jurassic and Early Cretaceous.