To keep the conversation civil I’m going to keep war out of the discussion.
But I have often pondered what are the ethical ramifications of revenge. I mean Hollywood is big on the idea but my gut instinct thinks that this wrong on so manny levels.
Edit: As a request I will add this
I am referring to taking justice in your own hands. Is their ethical ramifications on this.
It is said, in the tradition, revenge is for a hurt, justice is for a wrong. I read, somewhere, not long ago, in a thinker, the statement that: even a dog distinguishes between being kicked and being stumbled over. The pain of being stumbled over might be worse. Yet, by nature, if the dog is any measure, this is not something that deserves reprisal.
Eventually, starting from such dialectical and simple points, one can come to a theory of the injustice of revenge, and the justice of punishing a legal wrong based on intentionality. Yet, one can never leave it at that. And the discussion is ultimately thrown into the abyss, seeing how the instinctual opinions of dogs, may be nothing but conditioning, i.e., evolution, and of men, perhaps the trauma of a Freudian Father Figure. If all such considerations are baseless, or merely a matter of various forms of control, whether societal or through physical determination, etc...
Did you mean, however, that revenge means taking the law into one's own hands, rather than that of the authority of a public agency? Conifold, as you see, speaks correctly, in saying that here we have a vast area, and some qualification is needed to usefully attempt to elucidate and so to investigate the matter of a specific consideration.
The first thing comes to mind is the injunction:
An eye for an eye
This principle was to restrict vendettas, revenge, retaliation and punishments in that the punishment must be proportionate to the crime and not excessive. It was first enunciated in the Babylonian Code of Hammurabi. A similar principle is the Talmud. Judicially, it comes under the jurisdiction of lex talionis, where a lawcode prescribes specific punishments for specific crimes.
In Christianity, Jesus in the Sermon of the Mount said:
You have heard that it was said, "An eye for an eye and a tooth for a tooth." But I say to you, Do not resist the one who is evil. But if anyone slaps you on the right cheek, turn to him the other also.
That is forgiveness is important. A similar thought is urged in the Qu'ran:
In the Torah we prescribed for them a life for a life, an eye for an eye, a nose for a nose, an ear for an ear, a tooth for a tooth, an equal wound for a wound: if anyone forgoes this out of charity, it will serve as atonement for his bad deeds. Those who do not judge according to what God has revealed are doing grave wrong. (Qurʾān, 5:45)
This thought is also implicit - or so it seems to me - in the Bhagavad Gita where Arjuna is urged by Krishna to do his duty when he falters because he would be going to war against his kith and kin; eventually, he is so convinced. But in the final scene we see a vista of ruins.
The ethical issues imbalance and inequality as well as risk of injustice.
The same crime can lead to different punishments depending on who conducts the revenge. One person will beat you up and the other person will nail you to the wall with a nailgun.
There is also no guarantee that the punishment fits the crime, because it is decided upon and executed by one quite biased person, without considerations for such wider issues.
There is also the problem of punishing an innocent. A justice system has more resources and specially trained individuals available to ascertain guilt. A "do it yourself" revenge taker can very well mix up people, wrongly remember something or just get the wrong person - something that is rarely a part of the Hollywood storytelling.
