So why do people fight? Evolutionary theory and the causes of war

Azar Gat*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


The causes of war remain a strangely obscure subject in the discipline of International Relations. Although the subject is of cardinal significance, theories of International Relations address it only obliquely, and most scholars in the field recognize the lacuna only when their attention is drawn to it. While people have a good idea of the aims that may motivate states to go to war, an attempt at a strict definition of them is widely regarded as futile. This article seeks to show how the various causes of violence and war all come together and are explained within an integrated human motivational complex, shaped by evolution and natural selection. These interconnected causes of fighting - some of them confusedly singled out by various schools in IR theory, most notably within realism - include competition over resources and reproduction, the ensuing quest for dominance, the security dilemma and other prisoner's dilemmas that emanate from the competition, kinship, identity, and ideas.

Original languageEnglish
Pages (from-to)571-599
Number of pages29
JournalEuropean Journal of International Relations
Issue number4
StatePublished - 2009


  • Causes of war
  • Critique of IR theory
  • Evolutionary theory
  • Human motivation


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