"An eye for an eye" (, ) is a commandment found in the Book of Exodus 21:23–27 expressing the principle of reciprocal justice measure for measure. The earliest known use of the principle appears in the Code of Hammurabi, which predates the Hebrew Bible.
The law of exact retaliation (), or reciprocal justice, bears the same principle that a person who has injured another person is to be penalized to a similar degree by the injured party. In softer interpretations, it means the victim receives the [estimated] value of the injury in compensation. The intent behind the principle was to restrict compensation to the value of the loss.
Definition and methods
The term lex talionis does not always and only refer to literal eye-for-an-eye codes of justice (see rather mirror punishment) but applies to the broader class of legal systems that specifically formulate penalties for specific crimes, which are thought to be fitting in their severity. Some propose that this was at least in part intended to prevent excessive punishment at the hands of either an avenging private party or the state. The most common expression of lex talionis is "an eye for an eye", but other interpretations have been given as well. Legal codes following the principle of lex talionis have one thing in common: prescribed 'fitting' counter punishment for a felony. The simplest example is the "eye for an eye" principle. In that case, the rule was that punishment must be exactly equal to the crime.
In Babylonian law
In the legal Code of Hammurabi, the principle of exact reciprocity is very clearly used. For example, if a person caused the death of another person, the killer would be put to death.
Various ideas regarding the origins of this law exist, but a common one is that it developed as early civilizations grew and a less well-established system for retribution of wrongs, feuds and vendettas, threatened the social fabric. Despite having been replaced with newer modes of legal theory, lex talionis systems served a critical purpose in the development of social systems—the establishment of a body whose purpose was to enact the retaliation and ensure that this was the only punishment. This body was the state in one of its earliest forms. The principle can be found in earlier Mesopotamian law codes such as the Codes of Ur-Nammu of Ur and Lipit-Ištar of Isín.
The principle is found in Babylonian Law. If it is surmised that in societies not bound by the rule of law, if a person was hurt, then the injured person (or their relative) would take vengeful retribution on the person who caused the injury. The retribution might be worse than the crime, perhaps even death. Babylonian law put a limit on such actions, restricting the retribution to be no worse than the crime, as long as victim and offender occupied the same status in society. As with blasphemy or lèse-majesté (crimes against a god or a monarch), crimes against one's social betters were punished more severely.
In Ancient Greek law
Anaximander, teacher of Pythagoras: "The grand periodicities of nature are conceived of enacting cycles of retaliatory retribution." Socrates rejected this law.
In Hebrew law
In the law of the Hebrews, the "eye for eye" was to compensation to the value of the loss. Thus, it might be better read 'only one eye for one eye'. The idiomatic biblical phrase "an eye for an eye" in Exodus and Leviticus () literally means 'an eye under/(in place of) an eye' while a slightly different phrase (, literally 'eye for an eye; tooth for a tooth') is used in another passage (Deuteronomy) in the context of possible reciprocal court sentences for failed false witnesses. The passage in Leviticus states, "And a man who injures his countrymanas he has done, so it shall be done to him [namely,] fracture under/for fracture, eye under/for eye, tooth under/for tooth. Just as another person has received injury from him, so it will be given to him." (Lev. 24:19–21). For an example of being used in its regular sense of 'under', see Lev. 22:27 "A bull, sheep or goat, when it is born shall remain under its mother, and from the eighth day..."
The Bible allows for kofer (a monetary payment) to take the place of a bodily punishment for any crime except murder. It is not specified whether the victim, accused, or judge had the authority to choose kofer in place of bodily punishment.