In a totally forgotten book, Etienne Souriau, a mid 20th century philosopher had very daringly proposed to tackle straight on the question of the plurivocity of being not, as is so often the case in the history of philosophy, by offering variations on the one central mode -that is knowledge- but by insisting that there might exist entirely different modes. Feeding on the key notion that prepositions too are given in experience, as James said, it is one of the most extraordinary enterprises to give flesh to James' notion of pluriverse. Since the notion of mode of existence is so germane to the notion of regimes of enunciation, a close reading of Souriau's book is called for.