Over the decades from their initial encounter in Gotham City, the Joker has transformed from the Clown Prince of Crime to a mass murderer. He killed the second Robin, Jason Todd, paralysed Barbara Gordon (Batgirl), and shot and killed Lt. Sarah Essen, Commissioner Gordon’s second wife. As many times, the Batman captured the Joker, as many times the Joker escaped. Being insane, Batman knew the Joker will never be persecuted. Knowing as he did that the Joker will continue to escape and hurt and kill people, why did the Batman not kill the Joker?
Batman has said many times that he refused to kill because in killing, he is no better than the criminals that he is sworn to fight. But, the Joker? Come on, man.
I have been trying to understand Batman’s reluctance to kill and I come across this system of ethics named utilitarianism. This system will say, Batman kill the Joker because this will prevent all the murders he will commit in the future. While it is bad to kill, yet killing one life will be the saviour of many other lives.
Philosopher Philippa Foot and Judith Jarvis Thomson put forth the issue in form of a moral dilemma:

Imagine that a trolley is going down a track. Further down the track are five people who do not hear the trolley and will not be able to get out of the way. Unfortunately, there aren’t enough time to stop the trolley before it hits and kills them. The only way to avoid killing these five people is to switch the trolley to another track. But, unfortunately, there is one person standing on that track, also too close for the trolley to stop before killing him. Now imagine an innocent bystander standing by the track switch who must make a choice; do nothing, which leads to the death of five people on the current track, or act to divert the trolley to the other track, which leads to the death of the single person.

The Batman is in the place of the bystander. He is holding the Joker’s hands at the top of an unfinished office in the movie The Dark Knight. All he has to do is to let go and let the Joker fall to his death. Imagine the trolley scenario except the current track is onto the one person and switching the track will kill the five.
Do you think the Batman should kill the Joker?
Philosopher Thomson now suggest another scenario

There is a surgeon with five patients. Each of his patients is dying from failure of a different organ and could be saved by a transplant. Since there are no organs available by normal channels, the surgeon considers drugging one of his (healthy) colleague and removing his organs to use for transplants. 

By killing one, many will be saved. This is utilitarianism. This is similar to the trolley story. The death of one will save the five. Or is it? Do you agree? Is the choice of allowing the trolley kill one person the same as killing another person for his organs?

Do you think Batman should kill the Joker?
It would have been so easy for the Batman to kill the Joker. Batman is an expert exponent of many types of martial arts.
The philosophical system of utilitarianism will have not problem with Batman killing the Joker to prevent Joker from committing further crimes. As we have seen from our earlier posts about the trolley and the surgeon, it is not as straight forward as it seems.
In the Hush storyline, Hush asked the Batman, “How many lives do you think you’ve cost, how many families have you ruined, by allowing the Joker to live?…And why? Because of your duty? Your sense of justice?”
In utilitarianism, the end justifies the means. A popular proponent of utilitarianism is Peter Singer, professor of Philosophy in Princeton University and in the University of Melbourne.
However, there is another system of philosophy named deontology (nothing to do with dentists) in which the act is more important. When you decide “do not kill”, it means do not kill under any circumstances, irrespective of whatever good that killing may produce. Deontology is based on a sense of duty and the most well known proponent is Immanuel Kant. Of course, Immanuel Kant have never met the Joker.
“Is Batty a secret deontologist?” muses the Joker.
“I want my lawyer! Oh, that’s right, I killed him too” (from The Dark Knight)
In our consideration of why Batman did not kill the Joker when he have had so many opportunities to do so, it is obvious that he is not a follower of utilitarianism. Utilitarianism takes into consideration that the death of the Joker will save many people in DC comic universe.
While it may appear that Batman is a deontologist; that the act of killing is against his sense of duty to be not like the criminals he fights, however, his other actions do not support the conjecture. Batman as a masked vigilante is dangerously skirting the edge of the law and have been known to break the law when it suits his purpose. His Kantian ethics will not allow him to do this if he is a deontologist.
There is another system of ethics which come down to us from Aristotle, the great philosopher himself. Named virtue ethics, Aristotle postulated that the ethical behaviour of a person is not from his choice (utilitarianism), or his actions/duty (deontologism). It arises from who this person is. He calls these virtues or what we nowadays call character; compassion, justice, courage, and tolerance. One of the great virtue philosophers alive today is Alistair MacIntyre. There has been much talk of character/virtues in leadership especially political and religious leadership. Unfortunately these talks are of character/virtue flaws than of good strong character with integrity.
Does Batman has such good virtues that he is incapable of killing the Joker, no matter how much he wants to?
Our investigation into the existential question should Batman kill the Joker? has evolved to why the Batman did not kill the Joker.
We have established that Batman does not subscribe to utilitarianism and Kantianism (odeontologism). That left us to consider virtue moral theory. While unilitaianism focus on the consequences of the action, odeontologism on the duty of actor, virtue theory is about who the actor is, i.e. the character or virtues of the actor.
Batman/Bruce Wayne has very strong influential persons in his life. His father, Dr Thomas Wayne is a compassionate surgeon, industrialist and philantrophist. He believed in the goodness of people. Note that he organises the rich elite to help the poor during the depression in Gotham City and built the monorail system for the people. His death was partially due to the fact that he brought his family to the opera by monorail instead of by private car (see Batman Begins).
The butler Alfred was another influence and served as a surrogate father figure after the death of Thomas Wayne. Alfred exhibits strong elements of loyalty and integrity, looking after the family estates when Bruce was wandering around in search of himself. Though he disapprove of Bruce’s nocturnal activities, he restrict himself to sarcastic remarks while availing himself to rescue the Batman and offer medical treatment when necessary. It takes a strong character not to impose his will on others and to remind in the shadow of another.
Dr. Thompson is another who helped Bruce after the death of his parents. She provide the nurturing mother figure to balance Alfred’s Yang with her Yin. A competent doctor, she chooses to devote her life to helping the poor and the helpless in slum alley.
Thomas Wayne, Alfred and Thompson did not act out of a sense of duty but because of who they are. It is their characters that dictate their actions, not the other way around. Bruce Wayne must have pick up this moral theory from them. In the storyline, Bruce Wayne:Fugitive, Bruce Wayne has an identity crisis. Is he the Batman and Bruce the man behind the mask or Bruce Wayne and the Batman is the person behind the persona? As expected, the crisis was resolved when Bruce realise that the Batman was a means to an end (limiting the activities of the criminal elements by putting a fear in the criminal mind). This question resurfaced numerous times, for example in the story arch of No Man’s Land and Knightfall (and Knightend).
Batman does not kill the Joker because it is not in his nature or character to kill. Like Gandhi who resort to non-violence to resist an unjustice government, the Batman resort to non-lethal violence to resist a corrupt justice system and the criminal minds. It is in their strength of character that we must respect him.
previous posted at

.