Prior to his appointment as Dean of the Faculty of Arts in 2011, Mumford was Head of the Department of Philosophy from 2004–2007 and Head of the School of Humanities from 2009-2011.

The late philosopher George Molnar (1934–1999) published only four philosophical papers on metaphysics in his career, but his importance in the field should not be underestimated. After a return to the field, following a self-imposed absence, he was working on a book (“Powers”) and continued up until his sudden and untimely death in August 1999. The book remained unfinished until Mumford, who had previously been in contact with Molnar, in the summer of 1999, with the intention of giving feedback on the work (nearing completion), was approached to edit the remaining manuscript into a completed book. Mumford, along with several other figures in the field of metaphysics, including David Armstrong, were involved collaboratively in providing insight on Molnar’s work, and as a person, but the editing was left to Mumford, as was the writing of an introductory chapter to correctly present and establish the material laid out – something which Molnar did not get round to doing before his death. Armstrong states, “We can be very grateful to Stephen Mumford for making a volume from the much that we have. His excellent introduction serves in place of the introductory chapter that was left unwritten”. Mumford had discussed Molnar at a conference on Australian metaphysics, held in Grenoble (9–13 December 1999), but the colloquium – organised by Jean-Maurice Monnoyer, entitled “The Structure of the World: Objects, Properties and States of Affairs” – was to be the first official meeting of Mumford and Molnar as well. Mumford had considered this to be the end of the matter, but, in the spring of 2000, Mumford was contacted again concerning “Powers”. This time, however, it was through mutual friend Tony Skillen (lecturer in philosophy at the University of Kent) on behalf of Molnar’s former partner Carlotta McIntosh, who had given access to the manuscript and who shared it with Mumford. Although the book was, in places, complete and filled with promise, there was much work to be done on the later chapters – Mumford reflects on a conversation between himself and Armstrong on the way to the Grenoble colloquium, mentioning Molnar’s email stating the work was near finished, Armstrong replied: “it was near finished, in his mind”. The main theory of powers survives, and with Mumford’s help and editorial contribution is readily accessible.

Mumford is the sole-author of four books: Dispositions (1998), Laws in Nature (2004), David Armstrong (2007), and Watching Sport: Aesthetics, Ethics and Emotions (2011). Mumford has also edited two books: Russell on Metaphysics (2003) and George Molnar’s Powers: A Study in Metaphysics (2003). Most recently, Mumford co-authored, with Rani Lill Anjum, Getting Causes from Powers (2011).

Mumford was born in Wakefield, West Yorkshire. Mumford went on to read Philosophy and History of Ideas with Politics at Huddersfield Polytechnic (now University of Huddersfield) as his first degree. After Huddersfield, Mumford went on to the University of Leeds to take an MA in Philosophy of Mind. At Leeds, Mumford met Robin Le Poidevin who was to become his PhD supervisor. Mumford was awarded a PhD in 1994, for his thesis Dispositions and Reductionism, and was awarded a two-year lectureship at Leeds. Mumford left Leeds in 1995 for The University of Nottingham, where he has been Dean of the Faculty of Arts from 2011 to 2015.

Stephen Dean Mumford (born 31 July 1965) is a British philosopher, who is currently Head of Department and Professor of Metaphysics in the Department of Philosophy at Durham University. Mumford is best known for his work in metaphysics on dispositions and laws, but has also made contributions in the philosophy of sport.