P.M.S. Hacker is Emeritus Fellow and former Tutorial Fellow in philosophy at St John’s College, Oxford. He holds an Honorary Professorship at University College, London at the UCL Institute of Neurology at Queen’s Square. He has held British Academy and Leverhulme Senior Research Fellowships and visiting chairs in North America. He is the leading authority on the philosophy of Wittgenstein on whom he has written a dozen books. Together with M.R. Bennett he has written extensively on cognitive neuroscience. He is the author of 24 books, editor of 4 books, and author of 172 papers. In his works in the last decade and a half he has dedicated his energies to a tetralogy on human nature.