What if Deleuze's work embodied a more profound ambivalence than any in the history of philosophy? An ambivalence that bore more profoundly not upon this or that object or action, thing or idea, but rather upon sensibility itself and even the very being of the sensible. What if, in the very act of rehabilitating sensibility, Deleuze condemned it more brutally than Plato at his most Platonic or Descartes at his most Cartesian? What if everything in the philosophy that Deleuze first does and never abandons, the philosophy of difference in Difference and Repetition, began by double-crossing sensibility? What if sensibility jeopardised – even already ruined – philosophy on its eve? Even after an ‘affective turn’ that turns so much upon Deleuze, have we read Deleuze yet? Is ‘affect’ – not only but even and especially in Deleuze – ever entirely pure of a return to the ascetic tradition from which it would turn?

These questions might surprise, even antagonise, because everything points to the contrary. There's reason to credit Deleuze as the first philosopher to treat sensibility as sensibility, in its own right, as a singular and irreducible faculty. That which can only be felt, the purely sensible being of the sensible, what Deleuze calls the sentiendum in Difference and Repetition – affect in What Is Philosophy? – breaks palpably from previous conceptions of sensibility. Although they don't exhaust the history of philosophy or even the philosophers (or the works) from which I draw them, two classical conceptions in particular give an initial feel for the Deleuzian rupture. I’ll invoke them only schematically here.