Contributor(s): Professor Pierre Mayer, Professor Jan Paulsson | The 3rd LSE Arbitration Debate will confront Pierre Mayer and Jan Paulsson over the question whether international arbitrators can consider some otherwise applicable laws to be unlawful , as argued by Paulsson in his 2009 Lalive lecture and challenged by Mayer in an article in the Revue de l'arbitrage. Pierre Mayer is Professor of Private International Law at the University Pantheo Sorbonne - Paris I and a partner at Dechert LLP in Paris. Jan Paulsson is the co-head of the international arbitration and public international law groups of Freshfields LLP. Johnny Veeder QC is a Barrister at Essex Court Chambers.