There are many theories about the motivations for war, but no consensus about which are most common. Military theorist
Carl von Clausewitz said, "Every age has its own kind of war, its own limiting conditions, and its own peculiar preconceptions."
Psychoanalytic Dutch
psychoanalyst Joost Meerloo held that, "War is often...a mass discharge of accumulated internal rage (where)...the inner fears of mankind are discharged in mass destruction." Other psychoanalysts such as E.F.M. Durban and
John Bowlby have argued human beings are inherently violent. This aggressiveness is fueled by
displacement and
projection where a person transfers his or her grievances into bias and hatred against other
races,
religions,
nations or
ideologies. By this theory, the nation state preserves order in the local society while creating an outlet for aggression through warfare. The Italian psychoanalyst
Franco Fornari, a follower of
Melanie Klein, thought war was the paranoid or projective "elaboration" of mourning. Fornari thought war and violence develop out of our "love need": our wish to preserve and defend the sacred object to which we are attached, namely our early mother and our fusion with her. For the adult, nations are the sacred objects that generate warfare. Fornari focused upon sacrifice as the essence of war: the astonishing willingness of human beings to die for their country, to give over their bodies to their nation. Despite Fornari's theory that man's altruistic desire for self-sacrifice for a noble cause is a contributing factor towards war, few wars have originated from a desire for war among the general populace. Far more often the general population has been reluctantly drawn into war by its rulers. One psychological theory that looks at the leaders is advanced by Maurice Walsh. He argues the general populace is more neutral towards war and wars occur when leaders with a psychologically abnormal disregard for human life are placed into power. War is caused by leaders who seek war such as
Napoleon and
Hitler. Such leaders most often come to power in times of crisis when the populace opts for a decisive leader, who then leads the nation to war.
Evolutionary Several theories concern the evolutionary origins of warfare. There are two main schools: One sees organized warfare as emerging in or after the Mesolithic as a result of complex social organization and greater population density and
competition over
resources; the other sees human warfare as a more ancient practice derived from common animal tendencies, such as territoriality and sexual competition. The latter school argues that since warlike behavior patterns are found in many primate species such as
chimpanzees, as well as in many
ant species, group conflict may be a general feature of animal social behavior. Some proponents of the idea argue that war, while innate, has been intensified greatly by developments of technology and social organization such as weaponry and states. A study even found that civil war did occur in wild chimpanzee colonies, leading to a violent split in a group of chimpanzees. Psychologist and linguist
Steven Pinker argued that war-related behaviors may have been naturally selected in the ancestral environment due to the benefits of victory. He also argued that in order to have credible
deterrence against other groups (as well as on an individual level), it was important to have a reputation for retaliation, causing humans to develop instincts for
revenge as well as for protecting a group's (or an individual's) reputation ("
honor"). city-states over resources may have contributed to the eventual
collapse of the
Maya civilization by 900 CE. Crofoot and Wrangham have argued that warfare, if defined as group interactions in which "coalitions attempt to aggressively dominate or kill members of other groups", is a characteristic of most human societies. Those in which it has been lacking "tend to be societies that were politically dominated by their neighbors".
Ashley Montagu strongly denied universalistic instinctual arguments, arguing that social factors and childhood socialization are important in determining the nature and presence of warfare. Thus, he argues, warfare is not a universal human occurrence and appears to have been a historical invention, associated with certain types of human societies. Montagu's argument is supported by ethnographic research conducted in societies where the concept of aggression seems to be entirely absent, e.g. the
Chewong and
Semai of the Malay peninsula. Bobbi S. Low has observed correlation between warfare and education, noting societies where warfare is commonplace encourage their children to be more aggressive.
Economic s on fire during the
Gulf War, 1 March 1991 War can be seen as a growth of economic competition in a competitive international system. In this view wars begin as a pursuit of markets for
natural resources and for wealth. War has also been linked to
economic development by economic historians and development economists studying
state-building and
fiscal capacity. While this theory has been applied to many conflicts, such counter arguments become less valid as the increasing mobility of capital and information level the distributions of wealth worldwide, or when considering that it is relative, not absolute, wealth differences that may fuel wars. There are those on the extreme
right of the political spectrum who provide support, fascists in particular, by asserting a natural right of a strong nation to whatever the weak cannot hold by force.
Marxist The
Marxist theory of war is quasi-economic in that it states all modern wars are caused by competition for resources and markets between great (
imperialist) powers, claiming these wars are a natural result of
capitalism. Marxist economists
Karl Kautsky,
Rosa Luxemburg,
Rudolf Hilferding and
Vladimir Lenin theorized that
imperialism was the result of capitalist countries needing new
markets. Expansion of the
means of production is only possible if there is a corresponding growth in
consumer demand. Since the workers in a
capitalist economy would be unable to fill the demand, producers must expand into non-capitalist markets to find consumers for their goods, hence driving imperialism.
Demographic Demographic theories can be grouped into two classes, Malthusian and youth bulge theories:
Malthusian Malthusian theories see expanding population and scarce resources as a source of violent conflict.
Pope Urban II in 1095, on the eve of the
First Crusade, advocating Crusade as a solution to European overpopulation, said: This is one of the earliest expressions of what has come to be called the Malthusian theory of war, in which wars are caused by expanding populations and limited resources.
Thomas Malthus (1766–1834) wrote that populations always increase until they are limited by war, disease, or
famine. The violent
herder–farmer conflicts in Nigeria,
Mali,
Sudan and other countries in the
Sahel region have been exacerbated by
land degradation and population growth.
Youth bulge by country. War reduces life expectancy. A youth bulge is evident for
Africa, and to a lesser extent in some countries in West Asia, South Asia, Southeast Asia and Central America. According to
Heinsohn, who proposed
youth bulge theory in its most generalized form, a youth bulge occurs when 30 to 40 percent of the males of a nation belong to the "fighting age" cohorts from 15 to 29 years of age. It will follow periods with
total fertility rates as high as 4–8 children per woman with a 15–29-year delay. Heinsohn saw both past "Christianist" European colonialism and imperialism, as well as today's Islamist civil unrest and terrorism as results of high birth rates producing youth bulges. Among prominent historical events that have been attributed to youth bulges are the role played by the historically large youth cohorts in the rebellion and revolution waves of early modern Europe, including the
French Revolution of 1789, and the effect of economic depression upon the largest German youth cohorts ever in explaining the rise of
Nazism in Germany in the 1930s. The 1994
Rwandan genocide has also been analyzed as following a massive youth bulge. Youth bulge theory has been subjected to statistical analysis by the World Bank,
Population Action International, and the
Berlin Institute for Population and Development. Youth bulge theories have been criticized as leading to racial, gender and age discrimination.
Cultural Geoffrey Parker argues that what distinguishes the "Western way of war" based in Western Europe chiefly allows historians to explain its extraordinary success in conquering most of the world after 1500: The Western way of war rests upon five principal foundations: technology, discipline, a highly aggressive military tradition, a remarkable capacity to innovate and to respond rapidly to the innovation of others andfrom about 1500 onwarda unique system of war finance. The combination of all five provided a formula for military success....The outcome of wars has been determined less by technology, then by better war plans, the achievement of surprise, greater economic strength, and above all superior discipline. Parker argues that Western armies were stronger because they emphasized discipline, that is, "the ability of a formation to stand fast in the face of the enemy, where they're attacking or being attacked, without giving way to the natural impulse of fear and panic." Discipline came from drills and marching in formation, target practice, and creating small "artificial kinship groups: such as the company and the platoon, to enhance psychological cohesion and combat efficiency.
Rationalist Rationalism is an
international relations theory or framework. Rationalism (and
Neorealism (international relations)) operate under the assumption that states or international actors are rational, seek the best possible outcomes for themselves, and desire to avoid the costs of war. Under one
game theory approach, rationalist theories posit all actors can
bargain, would be better off if war did not occur, and likewise seek to understand why war nonetheless reoccurs. Under another rationalist game theory without bargaining, the
peace war game, optimal strategies can still be found that depend upon number of iterations played. In "Rationalist Explanations for War",
James Fearon examined three rationalist explanations for why some countries engage in war: • Issue indivisibilities • Incentives to misrepresent or
information asymmetry • Commitment problems Thirdly, bargaining may fail due to the states' inability to make credible commitments. Within the rationalist tradition, some theorists have suggested that individuals engaged in war suffer a normal level of
cognitive bias, but are still "as rational as you and me". According to philosopher
Iain King, "Most instigators of conflict overrate their chances of success, while most participants underrate their chances of injury...." King asserts that "Most catastrophic military decisions are rooted in
groupthink" which is faulty, but still rational. The rationalist theory focused around bargaining, which is currently under debate. The Iraq War proved to be an anomaly that undercuts the validity of applying rationalist theory to some wars.
Political science The statistical analysis of war was pioneered by
Lewis Fry Richardson following
World War I. More recent databases of wars and armed conflict have been assembled by the
Correlates of War Project, Peter Brecke and the
Uppsala Conflict Data Program. The following subsections consider causes of war from system, societal, and individual levels of analysis. This kind of division was first proposed by
Kenneth Waltz in
Man, the State, and War and has been often used by political scientists since then. Within the realist school as represented by scholars such as
Henry Kissinger and
Hans Morgenthau, and the
neorealist school represented by scholars such as
Kenneth Waltz and
John Mearsheimer, two main sub-theories are: •
Balance of power theory: States have the goal of preventing a single state from becoming a hegemon, and war is the result of the would-be hegemon's persistent attempts at power acquisition. In this view, an international system with more equal distribution of power is more stable, and "movements toward unipolarity are destabilizing."
Individual-level These theories suggest differences in people's personalities, decision-making, emotions, belief systems, and biases are important in determining whether conflicts get out of hand. For instance, it has been proposed that conflict is modulated by
bounded rationality and various
cognitive biases, ==Ethics==