A question was brought to my attention when discussing the graphic novel V for Vendetta, written by Alan Moore, which is about a man who was abused in a resettlement camp and is now seeking revenge against all of those who participated in abusing him. The question was this: when is revenge justifiable and when is it not justifiable? It was difficult to come up with a solid answer to this question because of how vague the question was. For the most part, it depends on the situation this question is applied to. In some cases, it might be justifiable to seek revenge and in other cases it might not be justifiable at all. It also depends on a person's perspective of each issue that this might apply to and the person's overall understanding of what is considered justifiable.
To prove that something is justifiable, one must be able to show that it is right or reasonable. In which cases is it right to seek revenge? It is common to think of revenge as going out to commit an act that will harm someone in someway that has harmed you or someone you know. For instance, if someone killed someone else's mother, the victim might seek revenge by killing the perpetrator's mother. Another example of a common revengeful act is if someone stole something from someone, the victim might steal something back or they might even try to do bodily harm to the person. Another way of looking at this question, though, is in terms of the justice system. When a victim of a crime presses charges against the perpetrator of a crime and they are punished for their actions, doesn't that count as revenge?
The problem with this question is that revenge comes in so many different forms. Sometimes, revenge is done at the same level at which the original crime was done. Other times, the revenge is a worse act than the original crime was done. In my opinion, in order to make revenge justifiable, it must be done on a reasonable level, meaning that it must be equivalent to whatever the first act done was.