Final answer:
The Democratic Peace Theory, suggesting that democracies are less likely to war with each other, is traced back to Immanuel Kant's work. Other philosophers, such as John Rawls, have elaborated on themes of justice and welfare in democracies that contribute to the idea of peaceful relations. The theory is a complex one influenced by a rich history of philosophical thought.
Step-by-step explanation:
The Democratic Peace Theory, which posits that democracies are less likely to engage in war with each other, has its roots in the ideas of various philosophers. However, the connection between democracy and peace can be comprehensively traced back to the writings of Immanuel Kant. In his essay "Perpetual Peace: A Philosophical Sketch" (1795), Kant lays out the groundwork for this theory, arguing that republican states (which he distinguishes from pure democracies) grounded in consent of the governed and functioning within a system of international laws will foster peaceful relations.
Other philosophers, such as John Rawls, have also discussed themes pertinent to the concept of democratic peace. Rawls's "A Theory of Justice" (1971) offers a vision of political society where institutions are arranged such that they ensure fair cooperation and respect the welfare of citizens, contributing to a stable and just society. Although not directly linking democracy to peace, the underpinnings of a society where justice as fairness prevails support the notions where peaceful coexistence might be achieved more readily through democratic means.
It is important to note that the concept of democratic peace is multifaceted and has been influenced by multiple historical and theoretical traditions. From the philosophical underpinnings laid out above to the modern interpretations and empirical research that continue to shape our understanding of the relation between democratic governance and pacific interactions among states, the topic encapsulates a breadth of scholarship spanning centuries.