“It was very possible that the true subject, the way it always was the true subject… was language.” Coming not for the first, or indeed last, time in Adam Thirlwell’s new novel, this turn-to-camera by its socialite protagonist, Celine, hints at what heart there is to the matter. The Future Future is the fourth novel from Thirlwell, twice a member of Granta’s Best Young British Novelists list, and known for his willingness to experiment with instability, unlikeability and other means of testing readers’ patience. It’s nominally set in revolutionary France, a world of scandal and salacious pamphlets that turn Celine – a fictional figure but with several parallels to the real salonnière, Juliette Récamier – into a “celebrity”.  In response, Celine throws parties and cultivates her own influential backers including colonists, financiers and playwrights, hoping to develop a new kind of soft power and arrest the lies being told about her and her sex life.…