These interpretations on the character state along with their motivations in an international system existing in anarchy provides us with an outlook on the causes of war from a realist perspective.
Carl von Clausewitz (1780-1831) who, writing in "On War" in 1831, proposed that war is not just a rational and controlled act, but also a "continuation of political activity by other means" (Cited in Brown and Ainley, 2009, p.115). Clausewitz was proposing that if states perceive war as something that is a necessary step so that they can promote their own interests and power, well then they will use it as a rational political tool. Kenneth Waltz and other modern realists have further built on Clausewitz idea of what causes wars and have also furthered and added to the idea. In Kenneth Waltz's writing in "Man, the State and War", he sets out three interconnected images of what causes wars. The first one, which keeps in line with a classical realist thought, is war has its origins in flawed human nature. This suggest that "the evilness of men, or their improper behaviour, leads to war" (Waltz, 2001, p.39). .
The second image that he proposes is that the inner administration of the state component is essential for us to understand its tendency towards war. The image has two beliefs that state that for survival in central conflict or civil war, a state must endorse an entity that is homogeneously unified. The third image that Waltz highlights the anarchy that exists in the international system. He proposes that as states have such interests that will all too often clash with the interest of other states, e.g. resources that may be scarce, and with no supreme authority to stop them "a state will use force to attain its goals if, after assessing the prospect for success, it values those goals more than it values the pleasures of peace" (Waltz, 2001, p.
