One of the most important and perennially debated philosophical questions is whether we can have knowledge of the external world. Butchvarov here considers whether and how scepticism with regard to such knowledge can be refuted or at least answered. He argues that only a direct realist view of perception has any hope of providing a compelling response to the sceptic and introduces the radical innovation that the direct object of perceptual, and even dreaming and hallucinatory, experience is always a material object, but not necessarily one that actually exists. This leads him to a metaphysics in which reality is ultimately constructed by human decisions out of objects that are ontologically more basic but which cannot be said in themselves to be either real or unreal.