Alain Badiou's writing on art has achieved a certain visibility recently as part of a wider debate on the new forms of sociability in art (relational and post-relational aesthetics). Its resistance to these new forms of politicization is based on a renewed commitment to art's negation and autonomy. In this, his writing takes its distance from the participatory and dialogic ethos of the moment, emphasizing art's powers of small-scale disclosure or subtractive difference. Yet he is no conventional modernist. His writing on art is intimately linked to a politics in which the subtractive negations of art are the precursor of, and a precondition for, the revolutionary destruction of capitalist relations. In this article I draw on Hegel and Adorno to reveal the weaknesses of this model of autonomy (Badiou fails to fully render art as a socialized category under capitalism) while defending the centrality of negation for any adequate theory of art's autonomy.