Bellum omnium contra omnes

Bellum omnium contra omnes, a Latin phrase meaning "the war of all against all", is the description that Thomas Hobbes gives to human existence in the state-of-nature thought experiment that he conducts in De Cive and Leviathan. The common modern English usage is a war of "each against all" where war is rare and terms such as "competition" or "struggle" are more common.

Thomas Hobbes' use

In Leviathan itself, Hobbes speaks of 'warre of every one against every one', of 'a war of every man against every man' and of 'a perpetuall warre of every man against his neighbour', but the Latin phrase occurs in De Cive:
Later on, two slightly modified versions are presented in De Cive:
In chapter XIII of Leviathan, Hobbes explains the concept with these words:
The thought experiment places people in a pre-social condition, and theorizes what would happen in such a condition. According to Hobbes, the outcome is that people choose to enter a social contract, giving up some of their liberties in order to enjoy peace. This thought experiment is a test for the legitimation of a state in fulfilling its role as "sovereign" to guarantee social order, and for comparing different types of states on that basis.
Hobbes distinguishes between war and battle: war does not only consist of actual battle; it points to the situation in which one knows there is a 'Will to contend by Battle'.

Later uses

In his Notes on the State of Virginia, Thomas Jefferson uses the phrase as he laments that the constitution of that state was twice at risk of being sacrificed to the nomination of a dictator after the manner of the Roman Republic.
The phrase was sometimes used by Karl Marx and Friedrich Engels:

In On the Jewish Question :
In Outlines of the Critique of Political Economy :
In a letter from Marx to Engels :
In a letter to Pyotr Lavrov, Engels is expressed clearly against any attempt to legitimize the trend anthropomorphizing human nature to the distorted view of natural selection:
It was also used by Friedrich Nietzsche in On Truth and Lies in a Nonmoral Sense :
Max Stirner used the term in his book The Ego and Its Own.
Rudolf Steiner describes it with the term "war of all against all" that will happen during a future epoch, when the human race will be submitted to a powerful selfishness.