The emotions of revenge and forgiveness are in some ways extreme opposite ends of an emotional scale. When we feel a desire for revenge, we are full of hate towards someone who we feel has hurt us. When we feel a desire to forgive, we are in a more generous state of mind, having let go of that hate. As we all know, you can't feel both of these emotions at the same time, and so when we experience hurt, arguably we have a choice as to whether to feel revenge or forgiveness.
Thinking about this is very timely, with Yom Kippur this week, when we spent a whole day collectively reflecting on whom we have wronged, asking ourselves "have we apologised?" - which might make it easier for the aggrieved person to forgive us. Many of us also used that long day of reflection to think about whether we should have forgiven others, who perhaps we have judged harshly, rather than continuing to bear a grudge towards them.
But I want to be realistic. We have to recognise that forgiveness is sometimes just not possible. After all, as Jews, we only have to think about what the Nazis did to our families to realise that forgiving them for committing their unbelievable atrocities is not going to happen. So, if there are some crimes that just cannot be forgiven, is our only choice to continue in a state of wanting revenge?
Revenge is a very dangerous state to be in, but revenge and forgiveness are not the only two options. There is a middle road.
In between these two emotional poles is empathy, which I would argue is more achievable than forgiveness, even if forgiveness might be held up as the ideal goal. And that, where we can't achieve forgiveness, empathy can still help us dissolve the dangerous emotion of revenge. Dangerous, because revenge simply perpetuates conflict whereas, through empathy, under some conditions, we could arrive at peace between former enemies. It's at least worth a try. I'm going to offer two examples, and I apologise that their content is quite shocking.
We must not forget that revenge is a very primitive emotion
Let me take you back, just a few weeks ago, to July 2015, to a village called Duma near the city of Nablus , on the West Bank. A Palestinian family, the Dawabshehs, were sleeping. It was just before dawn, when the silence was broken by the sound of a firebomb being thrown inside the family bedroom. Local people heard cries for help and when they got to the house they found the parents outside, on fire.
The rescuers went in and found Ahmad Dawabsheh, a four-year old child, standing in the living room, yelling for his mother. He was also badly burnt but they managed to get him to safety. Then they went back in to rescue the other son, little 18-month-old Ali Dawabsheh, but there was a huge explosion, and they couldn't reach him. Ali burnt to death. A week later, the father, Saad Dawabsheh, also died, as a result of the burns he received.
So who was responsible for this horrific, awful human tragedy in this Palestinian family? The most likely theory - which still remains to be proven - is that the arsonists were Israeli settlers. This is because someone had graffiti-ed on the outside of the Dawabsheh's home a Star of David, and the Hebrew word nekima, meaning "revenge".
Hundreds of enraged Palestinians turned out for little Ali's funeral, as the child's small body, draped in a flag, was carried through the village. Hamas called for retaliation, and Palestinians chanted for justice after feeling wronged.
Some of you may be thinking that the arson wasn't carried out by an Israeli settler, but instead was simply made to look like an Israeli did it, in order to put the blame on them. We will have to await the outcome of the investigations. But there is a strong possibility that what we have here are two parties, both driven by the dangerous emotion of revenge: Possibly an Israeli settler or settlers, who may have done this because of some perceived injustice towards them. And the Palestinian response - to what was a real crime that has been committed against a child, and a family.
Revenge is a very primitive emotion, more than three million years old, since it is seen in animals that evolved before humans. The biology of revenge involves the hormone cortisol which floods your brain, makes you "see red", and all you can think of is "fight or flight". But the ancient primitive desire for revenge simply perpetuates the cycle of tit-for-tat violence.
Is forgiveness a realistic alternative? We can't imagine that the Dawabshehs are likely to be able forgive the arsonists. They lost their baby, they lost their father. But there is a third option available to us: empathy. Rather than giving in to the desire for revenge, the Palestinians could try to imagine the arsonist's perspective. They might ask themselves: ''What has driven this man to want revenge''?
Using empathy, they could reasonably assume that the person who threw the firebomb, at that very moment, must have been suffering from a serious emotional disturbance. And using empathy, they might go one step further and ask themselves "Might the arsonist himself have experienced great loss?" Using empathy may switch the Palestinian from seeing the arsonist as the enemy, to seeing this deranged perpetrator as a tragic, flawed person they need to talk to, to arrive at a new understanding.
Equally, what if the arsonist had used empathy? What if he had stopped to imagine that Palestinians have the very same feelings of vulnerability and fear of threat, with the same capacity for feeling the awful, unimaginable pain that will never go away if you lost a baby from arson?
Empathy might have put brought down the emotional temperature sufficiently to have avoided the crime. Taking another person's point of view - one part of empathy - interrupts the revenge circuit in the brain and helps to reduce those dangerous feelings driven by hate.
Let's leave the Middle East, and turn to my second example. We're going back to a month before. It is June 2015, and we are in the Emanuel African Methodist Episcopal Church in Charleston, South Carolina. A Bible study meeting of black African-Americans is in full swing. In walks 21-year-old Dylann Roof , a young white man. He sits down, listening. As the group is discussing, young Dylann starts to disagree, stands up, pulls out a gun and shoots nine black people, all the time shouting out racist statements. The day after the killings Roof appeared in court via a video link. In the court were relatives of those killed in the massacre. One said to Roof: "You hurt me. You hurt a lot of people, but I forgive you." Another said: "I'm very angry (but) we have no room for hate. We have to forgive."
I watched this court case on the news, stunned that they were using the word forgiveness, not the word revenge. Forgiveness is a very different emotional response to being hurt. Forgiveness has been used in restorative justice programs- for example, after the end of Apartheid, in the Truth and Reconciliation process in South Africa.
But how realistic is it to feel the emotion of forgiveness? Do we really think that, if someone kills your 18-month-old toddler in Nablus, or your grandmother in Charleston, in a hate crime, you can just forgive them? It sounds unimaginable.
Forgiveness may be possible if the person who has wronged you apologises, and asks for forgiveness. And forgiveness may be possible if you can see the person who wronged you as less than fully responsible for their actions - for instance, a murder that occurs in the heat of the moment, or as the result of a psychiatric state.
Those who choose forgiveness often see it as a better way to live than to continue to live with hate, and as a way of re-humanising someone who has committed a crime. To forgive someone doesn't mean you condone what they have done, or forget what they have done. But to forgive assumes you have already used empathy. You are already seeing the aggressor's own feelings, perhaps of regret, of guilt, of having erred, or even simply their disability: their lack of awareness of the awful thing they have done.
When one sees Dylann Roof not just as someone who caused the terrible tragedy but as a tragic character himself - and we can assume that he, too, must have been seriously emotionally disturbed to have been able to do what he did - one can begin to feel some empathy towards him.
When one sees the arsonists in Nablus not just as arsonists, but as people who perhaps themselves have been traumatised by the cycle of violence, one can begin to seeing them as victims, too.
Empathy brings down our emotional temperature so that, instead of being blinded by the desire for revenge, we can make a different choice. Empathy involves a different circuit in the brain, and a different hormone called oxytocin.
While cortisol creates a state of anger or fear, where you see the other person as an enemy, oxytocin creates a calmer state where you can begin to see the other person as a vulnerable, flawed person who has done bad things, and where you can begin to feel sorry for them. Cortisol blocks oxytocin, and vice versa. You can't feel both at the same time.
When we feel wronged, we can make a choice: to give in to the primitive emotion of revenge, or to try to empathise - even with an aggressor - so that we don't rush to exact revenge, and instead begin to see the other person's point of view, a prerequisite for dialogue, and the first step on the road to peace.
Empathy is not a universal panacea, but could work under some conditions. In conflicts where actually both parties are victims, such as in the Israel-Palestine conflict, it helps if each partner can move away from seeing the other as an aggressor and instead see the other as vulnerable.
A relationship based on empathy between Mandela and De Klerk worked in ending Apartheid. On twitter, there are the seeds of a campaign called hashtag "Jews and Arabs refuse to be enemies".
And empathy can help guide our responses today, such as towards the refugees who today are desperately fleeing danger in Syria, where our compassion could save lives.