Peace is an elusive concept with many different meanings. Traditionally, it has been equated with the absence of war or violence, but such “negative peace” has limited value as it lumps wildly disparate situations together, such as rivalries (India–Pakistan) and close political relationships (e.g., European Union). Nevertheless, this conception remains the predominant approach in theory, research, teaching, and policy discourse. “Positive peace” definitions are much broader and encompass aspects that go beyond war and violence, but there is far less consensus on those elements. Conceptions include, among others, human rights, justice, judicial independence, and communication components. Best developed are notions of “quality peace,” which incorporate the absence of violence but also require things such as gender equality in order for societies to qualify as peaceful. Many of these, however, lack associated data and operational indicators. Research on positive peace is also comparatively underdeveloped. Peace can also be represented as binary (present or not) or as a continuum (the degree to which peace is present). Peace can be applied at different levels of analysis. At the system level, it refers to the aggregate or global conditions in the world at a given time. At the dyadic or k‑adic level, it refers to the state of peace in relationships between two or more states. Finally, internal peace deals with conditions inside individual states, and the relationships between governments, groups, and individuals. Aspects of peace vary according to the level of analysis, and peace at one level might not be mirrored at other levels.
Paul F. Diehl
Peace research is a component of the field of international relations (IR) that focuses on the causes of war and violence as well as the conditions of peace. The origins of peace research can be traced to the works of Plato, Thucydides, Hugo Grotius, Thomas Hobbes, and Immanuel Kant. The central debate in peace research revolved around the question of whether peace is to be defined simply as the absence of war and direct violence (“negative peace”) or the whether the concept encompasses both the absence of war and direct violence plus the presence of social justice (“positive peace”). Three primary waves of peace studies worldwide since its beginnings between the world wars can be identified: the first wave, roughly from the 1930s to 1960s, focused largely on the causes of war; the second wave was concerned with radicalization and democratization of peace studies; and the third wave saw the rise of two dominant fields—those of nuclear weapons, arms control and disarmament, and conflict resolution/management. During the 1990s, there was a renewed attention to research on topics such as sanctions, peacemaking, the concept of a culture of peace, environment, development, and conflict. Peace research and peace studies have in some ways brought about a transformation not only of dominant power structures, but also of the very concept of power itself. However, there are areas that need improvement, such as developing alternatives to armed conflict and injustice.