The causes of both civil and international wars have long been the subject of much debate and also academic study. Numerous methodologies have been employed, including those of the anthropologist, the demographer, the economist, the meteorologist, the philosopher, the psychologist, the social scientist, and the strategist. Each of them sheds light on the subject, but none provides on its own a satisfactory answer to the very wide-ranging question of what causes wars – and also how they can be prevented. Adam Roberts suggests that the absence of a unified theory of the causes of war is not a disaster. However, the present period of growing nationalism and great power rivalry forces us to look again at the causes of international as well as non-international armed conflicts.

Adam Roberts is Emeritus Professor of International Relations at Oxford University, and Emeritus Fellow of Balliol College, Oxford. He was one of the founding members of CCW and served on its Academic Board before his retirement, and is now Honorary Fellow and Member of the CCW Advisory Board.