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 (1642) and Leviathan (1651). 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.

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:

[...] ostendo primo conditionem hominum extra societatem civilem, quam conditionem appellare liceat statum naturæ, aliam non esse quam bellum omnium contra omnes; atque in eo bello jus esse omnibus in omnia.

I demonstrate, in the first place, that the state of men without civil society (which state we may properly call the state of nature) is nothing else but a mere war of all against all; and in that war all men have equal right unto all things.

Later on, two slightly modified versions are presented in Libertas (liberty):

[...] Status hominum naturalis antequam in societatem coiretur, bellum fuerit; neque hoc simpliciter, sed bellum omnium in omnes.
The natural state of men, before they entered into society, was a mere war, and that not simply, but a war of all men against all men.

Nam unusquisque naturali necessitate bonum sibi appetit, neque est quisquam qui bellum istud omnium contra omnes, quod tali statui naturaliter adhæret, sibi existimat esse bonum.

For every man by natural necessity desires that which is good for him: nor is there any that esteems a war of all against all, which necessarily adheres to such a state, to be good for him.

In chapter XIII of Leviathan, Hobbes explains the concept with these words:

Hereby it is manifest that during the time men live without a common Power to keep them all in awe, they are in that condition which is called War; and such a war as is of every man against every man. [...] In such condition there is no place for Industry, because the fruit thereof is uncertain: and consequently no Culture of the Earth; no Navigation, nor use of the commodities that may be imported by Sea; no commodious Building; no Instruments of moving and removing such things as require much force; no Knowledge of the face of the Earth; no account of Time; no Arts; no Letters; no Society; and which is worst of all, continual Fear, and danger of violent death; And the life of man solitary, poor, nasty, brutish, and short.

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