Naturaleza humana
Classical Realist theory explains international relations through assumptions about human nature. The theory is pessimistic about human behaviour and emphasizes that individuals are primarily motivated by self-interest and not higher moral or ethical aspirations. The behavior of states is theorized to be dictated by basic primal emotions, for example Thomas Hobbes described fear or aggression as fundamental motivations. Human nature is not seen to be changeable but only controllable when placed within societal boundaries. Classical realism takes a pessimistic view of human nature but the exact form this takes is debated as some classical realists focus on self-interest and a desire for survival as the primary aspects of human nature whilst, others believe in humans being inherently cruel, egoistic and savage.