The Philosophy of Law: Private Right, § 42: The Postulate of Public Right
From the conditions of Private Right in the Natural state, there arises the Postulate of Public Right. It may be thus expressed: ‘In the relation of unavoidable co-existence with others, thou shalt pass from the state of Nature into a juridical Union constituted under the condition of a Distributive Justice.’ The Principle of this Postulate may be unfolded analytically from the conception of Right in the external relation, contradistinguished from mere Might as Violence.
No one is under obligation to abstain from interfering with the Possession of others, unless they give him a reciprocal guarantee for the observance of a similar abstention from interference with his Possession. Nor does he require to wait for proof by experience of the need of this guarantee, in view of the antagonistic disposition of others. He is therefore under no obligation to wait till he acquires practical prudence at his own cost; for he can perceive in himself evidence of the natural Inclination of men to play the master over others, and to disregard the claims of the Right of others, when they feel themselves their superiors by Might or Fraud. And thus it is not necessary to wait for the melancholy experience of actual hostility; the individual is from the first entitled to exercise a rightful compulsion towards those who already threaten him by their very nature. Quilibet prccsumitur malus, donee securitatem dederit oppositi.
So long as the intention to live and continue in this state of externally lawless Freedom prevails, men may be said to do no wrong or injustice at all to one another, even when they wage war against each other. For what seems competent as good for the one, is equally valid for the other, as if it were so by mutual agreement. Uti partes de jure suo disponunt, ita jus est. But generally they must be considered as being in the highest state of Wrong, as being and willing to be in a condition which is not juridical; and in which, therefore, no one can be secured against Violence, in the possession of his own.
The distinction between what is only formally and what is also materially wrong and unjust, finds frequent application in the Science of Right. An enemy who, on occupying a besieged fortress, instead of honourably fulfilling the conditions of a Capitulation, maltreats the garrison on marching out, or otherwise violates the agreement, cannot complain of injury or wrong if on another occasion the same treatment is inflicted upon themselves. But, in fact, all such actions fundamentally involve the commission of wrong and injustice, in the highest degree; because they take all validity away from the conception of Right, and give up everything, as it were by law itself, to savage Violence, and thus overthrow the Rights of Men generally.