War

War is an armed conflict between the armed forces of states, or between governmental forces and armed groups that are organized under a certain command structure and have the capacity to sustain military operations, or between such organized groups.

It is generally characterized by widespread violence, destruction, and mortality, using regular or irregular military forces. Warfare refers to the common activities and characteristics of types of war, or of wars in general.

Total war is warfare that is not restricted to purely legitimate military targets, and can result in massive civilian or other non-combatant suffering and casualties.

The English word war derives from the 11th-century Old English words wyrre and werre, from Old French werre (guerre as in modern French), in turn from the Frankish *werra, ultimately deriving from the Proto-Germanic *werzō 'mixture, confusion'. The word is related to the Old Saxon werran, Old High German werran, and the modern German verwirren, meaning 'to confuse, to perplex, to bring into confusion'.

Anthropologists disagree about whether warfare was common throughout human prehistory, or whether it was a more recent development, following the invention of agriculture or organised states. It is difficult to determine whether warfare occurred during the Paleolithic due to the sparseness of known remains. Some sources claim that most Middle and Upper Paleolithic societies were possibly fundamentally egalitarian and may have rarely or never engaged in organized violence between groups (i.e. war). Evidence of violent conflict appears to increase during the Mesolithic period, from around 10,000 years ago onwards.

American cultural anthropologist and ethnologist Raymond Case Kelly claimed that before 400,000 years ago humans clashed like groups of chimpanzees; however, later they preferred "positive and peaceful social relations between neighboring groups, such as joint hunting, trading, and courtship". In his book Warless Societies and the Origin of War he explores the origins of modern wars and states that high surplus product encourages conflict, so "raiding often begins in the richest environments".

In War Before Civilization, Lawrence H. Keeley, a professor at the University of Illinois, says approximately 90–95% of known societies throughout history engaged in at least occasional warfare, and many fought constantly. Keeley describes several styles of primitive combat such as small raids, large raids, and massacres. All of these forms of warfare were used by primitive societies, a finding supported by other researchers. Keeley explains that early war raids were not well organized, as the participants did not have any formal training. Scarcity of resources meant defensive works were not a cost-effective way to protect the society against enemy raids. William Rubinstein wrote "Pre-literate societies, even those organized in a relatively advanced way, were renowned for their studied cruelty.'"

Since the rise of the state some 5,000 years ago, military activity has continued over much of the globe. In Europe the oldest known battlefield is thought to date to 1250 BC. The Bronze Age has been described as a key period in the intensification of warfare, with the emergence of dedicated warriors and the development of metal weapons like swords. Two other commonly named periods of increase are the Axial Age and Modern Times. The invention of gunpowder, and its eventual use in warfare, together with the acceleration of technological advances, have fomented major changes to war itself.