I am professor of theoretical philosophy at Freie Universität Berlin. I work in metaphysics, but I am most interested in the areas where metaphysics meets the philosophy of science, of language, or of action. Most of my work is focussed on the potentials (dispositions, abilities, and so forth) of individual objects and specifically on how to develop a theory of metaphysical modality (its metaphysics, its semantics, and its epistemology) in terms of them. More recently, I have become interested in various projects in the philosophy of action and in epistemology that make use of the notion of abilities, in particular in virtue epistemology.