“They would not know the name of Justice if these things did not exist.” (L&K, D55; cp. K 69, R, S 23)
It’s uncertain what “these things” refers to. Clement, who the quote comes from, suggests “laws.” In accord with that, the people would gain their understanding of justice from the existent laws. A favored interpretation however is that “these things” refers to “injustices,” as this aligns with a tendency in Heraclitus’ thought to see our understanding of some quality in reference to its opposite. The term for justice (Dike) is often used to refer to a judge’s decision about right or wrong actions. Robinson interprets “they” as referring to “the people.” The point then is that people understand a decision about rightful action against a background understanding of wrongful action. To understand the just we must understand the unjust.