https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3atext%3a2008.01.0395

Edit:

Plutarch, Non posse suaviter vivi secundum Epicurum, section 13

It's important in PD31 to go back to the original text to see what connotations those words in "neither harm nor be harmed" have.

Τὸ τῆς φύσεως δίκαιόν ἐστι σύμβολον τοῦ συμφέροντος εἰς τὸ μὴ βλάπτειν ἀλλήλους μηδὲ βλάπτεσθαι.

"To neither 'harm' others nor be 'harmed' oneself."

The word used is βλάπτειν and βλάπτεσθαι from βλάπτω

Henry George Liddell, Robert Scott, A Greek-English Lexicon, βλάπτω

and

Henry George Liddell, Robert Scott, An Intermediate Greek-English Lexicon, βλάπτω

Note that at the second link above, βλάπτω: "after Hom. to damage, hurt, mar, opp. to wilful wrong (ἀδικεῖν)"

That inclusion of ἀδικεῖν is very interesting, especially since it is literally what we would translate as "unjust" ἀ + δικεῖν.

ἀδικεῖν:

Greek Word Study Tool

That definition includes:

Quote

to be ἄδικος, do wrong (defined by Arist.Rh.1368b6 τὸ βλάπτειν ἑκόντα παρὰ τὸν νόμον, cf. ἀδίκημα）“, τῶν ἀδικησάντων τίσις ἔσσεται” those who have sinned, h.Cer.367; freq. in Hdt. and Att.; τἀδικεῖν wrong-doing, S.Ant.1059; τὸ μὴ ἀδικεῖν righteous dealing, A.Eu.85,749:— in legal phrase, do wrong in the eye of the law, the particular case being added in part., as “Σωκράτης ἀ. . . ποιῶν . . καὶ διδάσκων” Pl.Ap.19b, cf. X.Mem.1.1.1: c. acc. cogn., ἀδικίαν, ἀδικήματα, etc., Pl.R.344c, 409a, cf. Arist.Rh.1389b7; also “ἀ. οὐδὲν ἄξιον δεσμοῦ” Hdt.3.145; ἀ. πολλά, μεγάλα, etc., Pl.Smp.188a, al.; οὐδέν, μηδὲν ἀ. ib., al.:—“ἀ. περὶ τὰ μυστήρια” D.21.175, cf. IG2.811c154; ἀ. εἰς πόλιν, κτῆμα, Lib. Or.15.39, 31.7:—in games or contests, play foul, Ar.Nu.25, Arist. EN1123b32.

That section that is "defined by Arist.Rh.1368b6) refers to:

Quote from Aristotle, Rhetoric 1368b

after we have first defined acting unjustly.

Let injustice, then, be defined as voluntarily causing injury contrary to the law. Now, the law is particular or general. By particular, I mean the written law in accordance with which a state is administered; by general, the unwritten regulations which appear to be universally recognized. Men act voluntarily when they know what they do, and do not act under compulsion. What is done voluntarily is not always done with premeditation; but what is done with premeditation is always known to the agent, for no one is ignorant of what he does with a purpose. note The motives which lead men to do injury and commit wrong actions are depravity and incontinence. For if men have one or more vices, it is in that which makes him vicious that he shows himself unjust; for example, the illiberal in regard to money, the licentious in regard to bodily pleasures, the effeminate in regard to what makes for ease, note the coward in regard to dangers, for fright makes him desert his comrades in peril; the ambitious in his desire for honor, the irascible owing to anger, one who is eager to conquer in his desire for victory, the rancorous in his desire for vengeance; the foolish man from having mistaken ideas of right and wrong, the shameless from his contempt for the opinion of others. Similarly, each of the rest of mankind is unjust in regard to his special weakness.

So both Epicurus (or the Epicurean composer of the Kuriai Doxai, to hedge my bets) and Aristotle decided to use βλάπτω to define ἀδικεῖν!

"voluntarily causing injury (βλάπτω) contrary to the law. = τὸ βλάπτειν ἑκόντα παρὰ τὸν νόμον."

With both Aristotle and Epicurus using βλάπτω, they both recognize there is importance in the "voluntarily causing injury." Aristotle seems to ascribe more importance to the actions contrariness to the law, although he does state that there is also "unwritten regulations which appear to be universally recognized." Epicurus, on the other hand, seems to be more interested in the "contract" the συμφέροντος which is directly related to words that mean:

confer a benefit

be useful or profitable

useful, expedient, fitting, advantage

and so on...

Henry George Liddell, Robert Scott, A Greek-English Lexicon, συμφέρω

Epicurus seems more concerned with the usefulness or benefit of the agreement/contract/etc. than what the "letter of the law" is in a certain time and place.

I would *begin* to try to translate PD31 as:

The justice of nature (i.e., what is naturally just) is an agreement of mutual benefit between or among people to not voluntarily harm each other nor to not be harmed oneself deliberately by others actions.

This way, it rules out accidents and similar calamities. Epicurus wants to say that being harmed in a flood or killed by a wild animal cannot be claimed to be just or unjust. "To not be harmed" does not mean in any sense that you will never be injured or hurt. It all goes back to those voluntary actions for which we must take responsibility.

Are children born in a state of original honesty?

We didn't cover this very deeply, but there are excellent reasons for thinking that it's true. Everyone has experienced those moments when children say things that adults have been educated or conditioned or cultured into believing are tactless, rude, or unmentionable.

"Kids say the darnedest things" is a common phrase in America, but the question seldom asked is "why?"

Kids are honest, I think, because they have not yet been convinced of the perceived (and sometimes appropriate) need to lie.

Anyway, here is a study into the perception of judges to ascertain their views on the reliability of eye witnesses.

Judges Think Children More Honest But Less Reliable Than Adults, Says Queen's Study

Judges perceive child witnesses as being more honest than adults when testifying in court, but recognize that children's limited memory and communication…

www.sciencedaily.com

The conclusion: "Judges Think Children More Honest But Less Reliable Than Adults".

Piggybacking on Joshua's post:

https://www.apa.org/news/podcasts/speaking-of-psychology/why-kids-lie

Quote

So, the first time that a parent catches a child in a lie, it may come as an unpleasant surprise, but psychological research has found that lying is a normal part of childhood. In fact, it's a developmental milestone. It's only possible once children have developed some self-control and the ability to understand another person's mental state.

https://www.scientificamerican.com/article/decept…ish%20to%20dogs.

Quote

Many animals carry out disinformation campaigns aimed at others, within and across species. They mislead, cheat and lie in rampant acts of deception.

Moral of that second article: Humans are not special