Human nature is that quality that sets us apart from other living things; it is the definition of what we are.
The concept of human nature in international relations is embedded in the theories of international relations. Every International relations theory has its specific assumptions about human nature. The basic premise of these theories has its roots in human nature because in understanding the world and how it works, human nature is first considered. Philosophers maintain that in order for a political theory to hold any weight, it must first explain the concept of human nature.
And personally, I think this is one of the main reasons why new IR theories keep coming up, it is extremely difficult to explain all of human nature within one theory and just when one theory seems to have gotten in right, another theory comes up with a different aspect to human nature. And although there is some truth to each theories’ view of human nature, there are some inaccuracies as well and the only way to fully understand human nature if to look at it through all of these different lenses.