Preface Books like this often come with the promise of a new philosophy, or at the very least a new insight into the philosophy of mathematics. My book, indeed, presents a strange constellation between a so-called mathematical topos, contemporary physics, and philosophy, as I immerse myself in Gilles Deleuze’s and Alain Badiou’s thinking. Yet this is not a philosophy book per se, but rather a book on philosophy: its primary task is not to ‘argue’ or present a new ontology. Instead, as an ethnography, it reports how speculative sciences themselves reflect on logic and reason—the cornerstones of Western philosophy. It is not a theory of everything, but a book on such theories. That said, my book develops a boundary-breaking approach to the philosophy of science, with a view towards quantum physics and topos theory. This approach matures into a view of the world that could be called radically discursive. It is not just that there is a social or human aspect to the world that complements an otherwise non-discursive, ‘material’ realm, like some post-structuralists like Michel Foucault seem to assume as they replicate the old distinction between mind and matter in the discursive/non-discursivedivide. Nor is it about discursive materialism that perceives materiality as a performative effect of discourse. Instead, I ask, what if matter itself creates the basis of production of meaning and language? This question was put in motion in 2005 when I met Jacob Lurie—the world renowned wunderkind then working on his book Higher Topos Theory. This happened at a Harvard ski camp in northern New Hampshire, where we spent a week together talking maths, taking hot tubs and swirling in the snow. Not much later I was also introduced to Deleuze’s work, finding him particularly sobering after my exposure to mathematicians’ formalist obsessions. Yet it was Badiou who later brought me back to Lurie’s ‘higher’ mathematics—quite ironically, given Badiou’s unwavering distaste for category theory and ‘diagrammatics’. At least when it comes to the production of the act of counting—a procedure so crucial to Badiou—my discursive question about nature is echoed in quantum physics. In a somewhat Kantian twist, it asks on what conditions matter itself makes itself quantifiable. And quantifiable not only quantiatively, but rather in the sense of differentiating between different qualities ii