In the seventh installment in the series that presents the 40 Epicurean Principal Doctrines, it is time to take a look at how Epicurus did see justice. Before that I'd like to briefly point out how there are a lot of similarities in Buddhist and Epicurean thinking. It is an intriguing thought that Buddhist thinking could have seeped into Greece before the time of Epicurus, but we have no real knowledge of that happening.
However, the time-difference between those two thinkers is quite small and physical distance between their societies were great by the standards of that time.

The time of his birth and death of Gautama Buddha are uncertain: most early 20th-century historians dated his lifetime as 563 BCE to 483 BCE; recently opinion of a majority of scholars has gravitated to a time period within 20 years either side of 400 BCE for the Buddha's death, with others supporting earlier or later dates.
Epicurus lived 341 BCE to 270 BC. It is well possible that Buddhist influences have seeped into Greece by the time of Epicurus. However, it is quite likely that these ideas would have been mutated second hand impressions of the original ideas.

Epicurean thinking undoubtedly has much in common with Buddhism. On the other hand, wise men thinking about how to control the desires and needs of humans without a ballast of previous religious thinking may very easily come to very similar conclusions. The respective societies in which they did live had reached quite similar points of development.
However, now it is time for the 31th to 35th of the Epicurean Principal Doctrines in our little seriest that presents all of the 40 Epicurean Principal Doctrines.

Epicurus - Wikipedia

31. Natural justice is a pledge of reciprocal benefit, to prevent one man from harming or being harmed by another.

The basic values on which a human society is built on did interest Epicurus greatly. He did think a lot about the very fundaments of building and governing a society, besides thinking how an individual should act to reach a maximum level of inner harmony or ataraxia.
This doctrine is stating the very obvious. However, sometimes the obvious must be stated so that it can really be appreciated. There really are some people who really do not understand that morality is a thing that was created out of necessity to keep societies safe and sound. Morality has no 'divine' purpose. It exists mainly to keep people from coming to harm because of actions of other people.

These same people often have a great difficulty in seeing that morals do change tremendously with time also when theyt are dressed up as religious doctrines. For example, slavery was quite OK for also Jesus and his later Christian followers for 1700 years. Only the change in morality that was driven by the rise of humanistic values caused a change in this religion also.

32. 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.

The nature of justice and morality was very clear for Epicureans. They knew that these things are direct results of the demands that living in human social groups does present. They knew that humans themselves have created the rules because they make living in large groups possible and bearable.
This doctrine tells that one can diminish also the negative effects of the needs of society by staying aloof when possible and not binding oneself unnecessarily. This doctrine does not say that one should or need do it. It merely reminds that if one seeks mental peace, it can be achieved more easily the less one is tied to the needs of other people.

However, in my mind Epicurus does not postulate any anarchistic states. He just says that humans tend to make binding agreements with other humans and in this differ from other animals. This naturally means that all human societies are based on the same principles and 'anarchistic societies' exist only in the brains of certain people.
Epicurus is not speaking of barbarous people when he speaks about animals. He speaks about horses, dogs and cats who do not make similar 'binding agreements' as humans do.

33. 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.

This doctrine is as simple as they come. It just states that there is no divine or supernatural basis for justice in human societies. Justice is an agreement between people and it is being created out of the sorry necessity to protect people from actions of other people.

34. 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.

This doctrine tells that the real thing in keeping us on the narrow path is fear of being getting caught and getting stigmatized by the fellow humans. Epicurus was a realist, who did look at the nature of human beings without the ballast of myths and wishful thinking.
This kind of thinking may sound harsh. However, Epicurus saw that morality is a direct result of the demands of humans living in social groups. Actions simply must be judged on the basis how they affect the smooth working social group as a whole.

Such things are marked as immoral and forbidden that may threaten the harmonious working of the social group. The pressure of the social group is applied to those who do commit this kind of actions.
As humans are social creatures first and foremost, the worst thing that may happen to a human is getting rejected by his own social group and the fear of this is the main thing that keeps us from doing things that are forbidden by this group.

35. 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.

This doctrine deepens the idea that was presented in the previous one. It stated that fear of being caught is in the end the main force that keeps people from committing things that are forbidden by the society. In this doctrine, Epicureans points out that doing forbidden or immoral things secretly is a surest way to destroy ones peace of mind and mental stability.
As the peace of mind is the central or ultimate goal in all Epicurean thinking this doctrine urges people to act morally and justly for their own sake, to save them from mental pain and grief brought about by secret immoral actions. In practice, this means that rewards for moral and just way life are not reaped in any kind of afterlife. Epicurean thinking just points out the immediate personal rewards that living morally and justly brings with itself.

(This piece of writing was completely refurbished on 8th of July, 2012)