Violence is the expression of physical force against self or other, compelling action against one's will on pain of being hurt. Variant uses of the term refer to the destruction of non-living objects (see property damage). Worldwide, violence is used as a tool of manipulation and also is an area of concern for law and culture who take attempts to suppress and stop it. Violence can take many forms anywhere from mere hitting between two humans where there can be bodily harm, to war and genocide where millions may die as a result. It should be noted that violence can be non-physical as well.

Psychology and sociology

The causes of violent behavior physically aggressive behavior against another person."

Scientists disagree on whether violence is inherent in humans. Among prehistoric humans, there is archaeological evidence for both contentions of violence and peacefulness as primary characteristics.

Since violence is a matter of perception as well as a measurable phenomenon, psychologists have found variability in whether people perceive certain physical acts as 'violent'. For example, in a state where execution is a legalised punishment we do not typically perceive the executioner as 'violent', though we may talk, in a more metaphorical way, of the state acting violently. Likewise understandings of violence are linked to a perceived aggressor-victim relationship: hence psychologists have shown that people may not recognise defensive use of force as aggressive or violent at all, even in cases where the amount of force used is significantly greater than in the original aggression.

Riane Eisler, who describes early cooperative, egalitarian societies (she coins the term "gylanic", as it it widely agreed that the term matriarchal is inaccurate), and Walter Wink, who coined the phrase “the myth of redemptive violence,” suggest that human violence, especially as organized in groups, is a phenomenon of the last five to ten thousand years.

In a poll taken in 2003 in Chicago, Illinois, 67% of the people polled stated that the main cause of violence is argumentation.Fact: date=April 2009 When asked to clarify, one man said that violence is simply a product of arguments and that if arguments were avoided then violence could therefore also be avoided.

The “violent male ape” image is often brought up in discussions of human violence. Dale Peterson and Richard Wrangham in “Demonic Males: Apes and the Origins of Human Violence” write that violence is inherent in humans. However, William L. Ury, editor of a book called "Must We Fight? From the Battlefield to the Schoolyard—A New Perspective on Violent Conflict and Its Prevention” debunks the "killer ape" myth in his book which brings together discussions from two Harvard Law School symposiums. The conclusion is that “we also have lots of natural mechanisms for cooperation, to keep conflict in check, to channel aggression, and to overcome conflict. These are just as natural to us as the aggressive tendencies."