Materialising the Unthinkable: New series “Theories for the 21st Century” by guest editor Armen Avanessian and a proposal for a new philosophical materialism by the speculative realist Quentin Meillassoux. Jennifer Krasinski on Ed Atkins’s HD videos, and Hans-Jürgen Hafner rates Heinrich Dunst’s conceptual work. Oliver Basciano on Cosima von Bonin, and the Swedish performance artist and choreographer Mårten Spångberg shares his views on space, rhythm, expectation and embodiment with Filipa Ramos. Rita Vitorelli talks with the director of the Kunsthalle Vienna, Nicolas Schafhausen, on his curatorial approach and commitment to discourse.