This chapter demonstrates how Lyotard’s aesthetic theory provides the basis for a new interpretation of Yves Klein which provides an alternative to his common reception as a Conceptual artist. Through the different activities of philosophy and art, Lyotard and Klein both explore the nature of sensibility through an investigation of matter. Both paradoxically conclude that matter is in a sense immaterial. Lyotard understands matter as that part of an artwork which is diverse, unstable, and evanescent: in music, this corresponds to nuance and timbre, and in painting, to colour. Klein develops his meditation on matter firstly through his monochrome “propositions,” calling attention to pure colour (in particular, blue), which he theorises as stabilisations of energy. Beyond this, Klein invents “immaterial” works, such as the famous Void exhibition and his Zones of Immaterial Pictorial Sensibility. This chapter develops the confluences between Lyotard’s and Klein’s reflections on “immaterial matter,” and seeks to show how the results achieved in each area of activity (philosophy and art) can contribute to the other.