Owen Griffiths is Director of Studies for Philosophy and a Teaching By-Fellow in Logic and Metaphysics at all levels. He received his PhD from Cambridge and has subsequently worked in Oxford, the LSE and Cambridge. His research is in philosophical issues at the heart of logic. Under what circumstances is an argument valid? Is there one correct system of logic, or many? What are the uses of non-classical systems of logic? His main current research project is a monograph One True Logic, co-authored with Prof. Alex Paseau, Oxford. They defend a strong infinitary logic as the correct one for reasoning in all domains.