Natural justice is a pledge of reciprocal benefit, to prevent one man from harming or being harmed by another.
Those animals which are incapable of making binding agreements with one another not to inflict nor suffer harm are without either justice or injustice; and likewise for those peoples who either could not or would not form binding agreements not to inflict nor suffer harm.
There never was such a thing as absolute justice, but only agreements made in mutual dealings among men in whatever places at various times providing against the infliction or suffering of harm.
Injustice is not an evil in itself, but only in consequence of the fear which is associated with the apprehension of being discovered by those appointed to punish such actions.
It is impossible for a man who secretly violates the terms of the agreement not to harm or be harmed to feel confident that he will remain undiscovered, even if he has already escaped ten thousand times; for until his death he is never sure that he will not be detected.
In general justice is the same for all, for it is something found mutually beneficial in men’s dealings, but in its application to particular places or other circumstances the same thing is not necessarily just for everyone.
Among the things held to be just by law, whatever is proved to be of advantage in men’s dealings has the stamp of justice, whether or not it be the same for all; but if a man makes a law and it does not prove to be mutually advantageous, then this is no longer just. And if what is mutually advantageous varies and only for a time corresponds to our concept of justice, nevertheless for that time it is just for those who do not trouble themselves about empty words, but look simply at the facts.
Where without any change in circumstances the things held to be just by law are seen not to correspond with the concept of justice in actual practice, such laws are not really just; but wherever the laws have ceased to be advantageous because of a change in circumstances, in that case the laws were for that time just when they were advantageous for the mutual dealings of the citizens, and subsequently ceased to be just when they were no longer advantageous.
(Epicurus Principal Doctrines)
Epicurus’ view of ethics is an early contractarianism – the idea that our ethics are formed through mutual agreement under self-interest. Most philosophers would describe contractarianism as arriving from Hobbes, Locke, and Rousseau (variously around the 1760s) culminating in Rousseau’s work (1762) “The Social Contract”
Rousseau’s social contract is an extended argument intending to replace the divine right of kings – the idea that god mandates our rulers and they rule by divine favor instead of dumb luck – with something more grounded on the republican sentiment of the times. In Rousseau’s view, everyone participates in society by giving up some of their natural rights in return for other privileges that they attain through the community effort of society.
The problem with contractarianism, of course, is that the fair exchange of powers entails an understanding of those exchanges, or it’s not fair. It also entails that both parties actually do what they say they are going to do. Epicurus tries to head off this objection with his point:
It is impossible for a man who secretly violates the terms of the agreement not to harm or be harmed to feel confident that he will remain undiscovered, even if he has already escaped ten thousand times; for until his death he is never sure that he will not be detected.
In Epicurus’ view, the tax-cheat who bolsters their already vast fortune by avoiding paying into the common purse is punishing himself by knowing that he may get caught and punished; “A coward dies a thousand times before his death, but the valiant taste of death but once.”
It seems naive to me that someone as wise as Epicurus would rest his hopes on the social insecurity of his fellow man. Perhaps it was a function of his time – smaller groups of people such as Epicurus’ little anarchist colony are easier to balance and self-police, whereas today’s societies of hundreds and thousands of millions offer far too many places for people of bad intent to hide.
Epicurus makes a mistake in his last piece, too, in which he appeals to a concept of “justice in actual practice” – which is, what? His is a fairly common mistake made by consequentialists and contractarians, that people will suddenly magically see and agree when something is clearly wrong. I’m sure that even in Epicurus’ time there was enough history that he ought to have been able to see that’s not how people actually behave. To make mutually beneficial contracts, the contracting parties must be equal, knowledgeable, and aware – capable of autonomous action. The fact of social inequality renders such contracts null and void.