Which of the following thinkers is known for advocating for peace organizations in the 18th century?

Immanuel Kant is recognized for his advocacy of peace organizations in the 18th century, primarily through his essay "Perpetual Peace," published in 1795. In this seminal work, Kant outlines his vision for a peaceful global order, arguing for the establishment of a federation of free states that would cooperate to prevent war and promote lasting peace. He believed that democratic governance among nations would foster peace, as leaders accountable to their citizens would be less likely to engage in wars. Kant's ideas laid the groundwork for modern concepts of international relations and organizations, influencing later thinkers and the development of institutions aimed at maintaining peace.

Other philosophers, like Thomas Hobbes and Montesquieu, provided valuable insights into human nature and governance but did not specifically advocate for peace organizations in the same way. Denis Diderot contributed to Enlightenment thought as well, but his focus was more on the pursuit of knowledge and the critique of religion, rather than establishing frameworks for peace among nations. Thus, Kant stands out for his direct and profound commitment to the idea of organized efforts toward achieving peace.