Doing Good by Doing Evil

I’m trying to understand one thing after my son posed a question to which I had no answer.

Abortion is always wrong because it’s an intrinsic evil to kill an innocent person. However, if I kill someone in self-defense, it’s not a sin. But how so if killing someone is always an evil? A lighter example is that of incarcerating a thief, as taking someone’s freedom to come and go is also an evil. So, this is the question that my son asked: do the ends justify the means? I know that the answer is no, but I couldn’t explain why. :confused:

Can anyone help this grown man answer this child’s question?


Killing someone is always a grave act but is not always evil. It may or may not be sinful. In your example of self defense, the primary action was to defend your own or a loved ones life but someone might be killed in the process. If you had a reasonable way to protect yourself without killing someone and chose to kill them anyway, it would be gravely wrong.

Notice I say the primary “action” not “intent”. This is where the abortion argument fails. Some abortion advocates say that if the intent is to save the mother’s life, the act of killing the baby is ok. But that would be wrong. It isn’t the intent - it’s the action.

One can never commit an evil act even if good results from it.

Think of it this way:
The “Good Thief” was crucified next to Jesus, repented and was forgiven, but Jesus did not free him {even though he could have} because we are bound to societies laws, as well as God’s law.

There are consequences to breaking the rules; whether they are our local, state or federal laws, just as their are consequences to breaking God’s Law.

There is nothing in the bible that says “Thou shalt not punish the unjust”.

That’s how I’ve always understood it.

We’re on the same page, but let me put my son’s shoes and ask back: my pulling the trigger of a gun in self-defense embodied the intent and the action of killing an aggressor. How’s that not sinful, or at least not mortally sinful?

I’m just trying to have a water-tight answer to my son. :thumbsup:


Murder is the intentional taking of a life; intentionally depriving someone of life.

Killing someone, even in self defense, is objectively evil… but lacks the essence of “Free Will” because fear of harm to one’s family tends to have an over powering effect. No free will, no mortal sin.

I don’t know about you but if a burglar is coming at me, my intent is not necessarily to kill him, but to stop him.

If you kill someone accidentally, you lack full knowledge. No full knowledge, no mortal sin

However, if you kill someone “accidentally” during the commission of a crime, for example, robbing a bank… it is a mortal sin.

Killing someone is NOT “always” evil.

Killing an *innocent *person is always gravely wrong. An unjust aggressor seeking to take your life is **not **innocent. They cease to be innocent when they become an aggressor. You may use force to repel them, lethal force if necessary.

No it is not always an evil.

No, the ends cannot justify the means. The means must also be moral.

But, in both of the examples you gave, the means are moral.

I suggest you review the Fifth Commandment in its entirity with your son. Both of these things (killing an aggressor and imprisonment) are covered there.

To put it simply, **if your intention was to defend yourself **and if **the aggressor’s intention was to kill you **or to mortally wound you and if there was nothing else that you could do at that moment (like running away or shooting the bullet in his leg so that he would not get killed), then you could kill him (not with the intention of killing a human being, but with the intention of protecting yourself) and it would not be a sin.

There’s a passage in the Bible which talks about something similar. It might be helpful to you.

“If a thief is found breaking in, and is struck so that he dies, there shall be no bloodguilt for him; but if the sun has risen upon him, there shall be bloodguilt for him.” (Exodus 22:2-3)

I agree with this.:thumbsup:

Murder is always wrong. Killing is not always wrong. That’s the distinction.

Force isn’t intrinsically evil. Using force to try to murder someone is evil, but if someone is currently doing that, it is ok to use force to try to stop them, even if it results in their death, since the whole way force works is to counter other forces.

If the unjust aggressor dies it he who is guilty for his own death, not you. He intentionally placed himself in that position, not you.

This is from the CCC:




The legitimate defense of persons and societies is not an exception to the prohibition against the murder of the innocent that constitutes intentional killing. "The act of self-defense can have a double effect: the preservation of one’s own life; and the killing of the aggressor. . . . The one is intended, the other is not."65

2264 Love toward oneself remains a fundamental principle of morality. Therefore it is legitimate to insist on respect for one’s own right to life. Someone who defends his life is not guilty of murder even if he is forced to deal his aggressor a lethal blow:

If a man in self-defense uses more than necessary violence, it will be unlawful: whereas if he repels force with moderation, his defense will be lawful. . . . Nor is it necessary for salvation that a man omit the act of moderate self-defense to avoid killing the other man, since one is bound to take more care of one’s own life than of another’s.66


All good answers, but what’s nagging is that the means to stop the aggressor is to kill him. I can’t honestly say that I wouldn’t have the intent to kill someone in self-defense. Probably what would go through my mind would be:

  • Oops, he’s going to kill me, so I’ll kill him before he can do me any harm, since I have no other option besides using lethal force.

Not having to find myself in this situation, thank God, I think that the intent to kill would be there, even if to defend myself.

My son caught me short-handed here, because I know that moral assessments can be very tricky. That’s why I just try to follow what the Holy Mother Church teaches (yes, I let her do most of the thinking, just like I let doctors do most of the thinking when treating me).


I guess that the self-defense case is clearer to me now. The aggressor is indeed not innocent.

I guess that incarceration is only an evil if the prisoner is innocent, right?

But then it seems that we approach the slippery slope of moral relativism, I’m afraid. Why is killing or incarceration good means only when the one receiving such actions is guilty of evil? Is it guilt of the receiver of an action that determines whether the act is evil?


I see your point and perhaps someone has a good answer that refers to Church teaching.

You are not intending to kill him. You are intending to get him to stop trying to kill you. That means lethal force may be needed. Your real intent is to stop him. Right?

It doesn’t have to be, but it can be. If you an stop someone by whacking him in the knee cap, by all means do so.

But, if armed thugs break down your door, using lethal force may be all that is available to protect your family and yourself.

The guilt of the “receiver” is only relevent b/c it affects your intent.

If someone attacks you, your intent is to defend yourself, the assailant’s death is an unintended consequence. This is known as the principal of double effect. Since the first effect (self-defense) is moral, the second effect (the killing) is permissible.

God Bless

Not really. Killing and incarceration are not intrinsically evil.

Incarceration isn’t even a relative evil. Slavery is evil but it isn’t necessarily unjust to deprive some one of his/her ability to go where ever he/she wishes.

Murder is. It doesn’t matter if you murder a guilty or innocent person, it is still murder.

I can’t really sail that the assailant’s death in unintended. His death was the device to achieve my own defense, in other words, his death is more than a side-effect, but a means to effect my self-defense. Or am I missing something?


Yes, that’s the end to which, it seems to me, killing is a means…

Am I being logic or fallacious? :confused: I mean, the assailant’s death is a mean to achieve an end, it’s a mean chosen among many according to the situation and willfully exercised, as in one has to aim and pull the trigger to kill the assailant. It’s more than a mere side-effect of defending oneself, as it would undoubtedly be the case if one pushed an assailant and he falls through the window from the 5th floor. It’s an intended consequence of pulling the trigger.

Gosh, someone help me out! I can’t answer this to my son with a poker face, he’ll notice. Children ask such darn questions… :blush:


I agree with 1ke. Furthermore, while police officers and military personnel might be responsible for using lethal force when it was unnecessary, the average citizen doesn’t go to regular target practice or study strike zones. My father required that I carry a loaded pistol under my seat while driving the 300+ miles of mostly wilderness to and from college. He took me out on several occasions to teach me how to use it, and he cautioned me strongly to shoot for the torso, the largest part of the body, so as not to risk missing my aggressor (which could still happen).

If a person is in the sort of life-threatening situation during which force is required, there will be only seconds, or fractions thereof, in which to take aim and strike. During that time, I can guarantee that the only thing going through the average citizen’s head will be how to knock him down in such a way that he will no longer be able to attack. There is nothing morally illicit about it.

I seriously doubt that most of the people who shot and killed their violent aggressors did so with the intention of killing. The intention is to do what it takes to stop the attack. Killing, in many if not most cases, is an unintended side-effect of stopping the assailant.

So you could put it to Junior this way: If a person kills an attacker unintentionally while defending himself, he is not sinning. If a person kills an attacker intetionally, but that was the level of force required to stop him, he is not sinning. However, if a person kills an attacker intentionally, when he knows lethal force is not necessary, and he is capable of using less force and accomplishing the same task, then he is sinning.

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