Roger W. Sperry received the Nobel Prize for Physiology in 1981 for his outstanding scientific achievements in connection with the study of people with severed brain commissures. Sperry linked the results of his research to philosophical considerations pertaining to the conscious mind of human beings and its place in the natural sciences. He was interested in the philosophical question of whether or not the severing of the cerebral hemispheres constituted a violation of the unity of consciousness. Sperry’s explanatory account of (...) mind-body interaction forms part of a broadly construed theory of emergent interactionism – one that also purports to guarantee the unity of consciousness. In this article, I first present an intellectual profile of Sperry, outlining the evolution of his philosophical-scientific analyses. I then outline the emergence and flourishing of theories of emergence, along with the elements essentially associated with them. Using this as a basis, I go on to consider Sperry’s account of emergent interaction more closely, focusing on his understanding of downward causation. In conclusion, I show how his theory corresponds to a version of emergent interactionism, and seek to address some criticisms leveled against it. I also aim to establish how far this theory can be said to answer the question of the conscious character of mental states. (shrink)