Is it ethically wrong to kill an innocent person (or people) for the purpose of self preservation? Are there ethical theories that cover this?

An example may be a traffic situation whereby one can either divert their own vehicle into a wall risking their own life, or striking pedestrians, saving themselves.

I know for example utilitarian principles of ethics that imply what is right and wrong are dependent on maximising the greatest good for the greatest number, but are there exceptions for self-preservation in this framework? What about other ethical frameworks?

  • It is not that easy even in the case of utilitarian philosophy as determining the best outcome is too hard problem. – rus9384 Mar 24 '18 at 1:57


There are different ethical perspectives from which your question can be answered. This is clear from the first two replies. I suggest an approach from the side of rights. We are not all Kantians or utilitarians or signed up to virtue ethics but we (nearly) all use the concepts of rights and justice. It enters into virtually all our everyday moral arguments. I might add that it is a part of ordinary moral thinking that there are times when it is permissible intentionally to kill another person in self-defence. What principled moral defence from the viewpoint of rights can this axiom be given ?


We need an argument, not a statement of general positions, to see what the basis of the moral right of a potential victim to kill a morally innocent 'aggressor' - an innocent source of lethal danger - actually is or might be.


Judith Thomson tries to define the basis as follows :

According to [Thomson], if the aggressor holds no right to kill you (i.e., his aggression is not a response to a lethal threat you pose to him), you may kill him just because otherwise he would kill you.Hence, killing an aggressor is morally justified, even if he is free of fault in committing the particular aggression that threatens your life. Culpability has nothing to do with the right to self-defense, since an agent who exercises this right is not an agent of justice. The major argument Thomson advances appeals to the presumption against exercising private violence (I call this presumption the Weberian Presumption*). She takes it as almost self-evident that the Presumption cannot be defeated either by the aggressor's being liable to harm, or by his deserving it. ... She infers that it is defeated simply because the aggressor is about to kill someone and has no right to do so. ( Yitzhak Benbaji, 'Culpable Bystanders, Innocent Threats and the Ethics of Self-Defense', Canadian Journal of Philosophy, Vol. 35, No. 4 (Dec., 2005), p.586.)

[*'Weberian' refers to Max Weber's view of the state as having a monopoly of the exercise of legitimate violence. The 'presumption' is against the exercise of legitimate violence being 'privatised', transferred to an individual.]

What are we to make of Thomson's argument ? Let's read Benbaji a little more :

Thomson's basic claim is simple: you have the right to kill an aggressor in self-defense if he would otherwise kill you (while he holds no right to do so). Indeed, you have this right, because otherwise the aggressor would kill you. But what if the person whose being killed is necessary for preventing your death became an aggressor through no fault of his own? For example, what if the aggressor hallucinates that you are about to kill him? What if he is under the influence of drugs that cause him to be extremely aggressive? Furthermore, imagine that the one who is about to kill you is not an aggressor at all. You are sitting on a bench, and due to some cause, a man is falling on you - someone pushed him, or he lost his balance, or whatever. It turns out that, unfortunately for both of you, unless you blow him to pieces with a gun you have handy, he will crush you. Do you have the right to defend yourself against such an innocent threat? Thomson answers affirmatively. You are allowed to kill anyone who would otherwise kill you. True, the falling man won't kill you by any action of his, but still, he would kill you the way a stone can kill you - by falling on you. And he has no right to do so. (Benbaji, p.587.)


The argument generalises. If I have the moral right to kill in the situation described (the gun case) then so has anybody else similarly situated. It is not a private right.

The argument does not cover all cases of killing an innocent person for the sake of self-preservation. If someone is spraying bullets at me, the argument does not justify my grabbing an innocent person and using them as a shield.

Yet a serious objection to the argument seems to be this. Suppose that in the gun case I could only kill the innocent aggressor by firing a gun that would detonate a bomb that would (a) kill a large number of other innocents and (b) also kill me. These are situational factors that Thomson's argument does not consider. It is hard to see how her self-defence argument would pass the test of these extra factors.


If I kill through murderous aggression, then I kill disrespectfully. I am willing to accept that Kantian considerations of respect for persons apply here. Equally if I protect myself from murderous aggression I am protecting myself from the intention of being disrespectfully killed. Here also I recognise the relevance of Kantian considerations. I see the right to kill an innocent person in self-defence in terms of the right to protect my most basic interest, that of staying alive. Specifically, the right to kill an innocent threat, X, derives from the unfortunate fact for X, that X has infringed my claim against X that X not threaten my most basic interest (staying alive). A Kantian might note that though this argument is not based on respect for persons, it is capable of universalisability.


J. Thomson, 'Self-Defense', Philosophy and Public Affairs 20 (1991), 283-310.

Y. Benbaji, 'Culpable Bystanders, Innocent Threats and the Ethics of Self-Defense', Canadian Journal of Philosophy, Vol. 35, No. 4 (Dec., 2005), 585-622.

J.H. Beale, 'Homicide in Self-Defence', Columbia Law Review, Vol. 3, No. 8 (Dec., 1903), 526-545.

  • I liked the detailed and history in your response but I would like to mention some conceptual issues. There should be no such thing as killing an innocent. If I come at you with deadly force I am not innocent. Secondly I would say that normative ethics would say taking a life unnecessarily would be immoral. That is a black belt who can disarm the attacker ought to disarm and NOT kill because he has moral code and control over his actions. To kill an intruder in your house JUST BECAUSE is an excuse not to act in a mature and rational manner. So many homeowners do this it is deplorable. – Logikal Apr 5 '18 at 19:24
  • Thank you. If someone comes at me with lethal force because they have been propelled beyond their control by some third party, that leaves them innocent, I think. Do you disagree ? – Geoffrey Thomas Apr 5 '18 at 20:48
  • I would be curious to what that third party could be. Secondly if you can control your actions and not kill this is the mandate I express. You could restrain but you kill instead like the immoral home owners . If I threaten you to do the dirty work or else I kill your family I would still not kill you provided I have skills to stop by preserve life. I would say my obligation is to find ways to stop acts of violence without killing before anything happened. Self defence done proper you are like an adult compared to a child. Would one kill if the attacker was a 10 year old girl instead? – Logikal Apr 5 '18 at 21:42
  • Do you believe it is always wrong in all circumstances to kill in self-defence ? If that is your position, then no argument I can offer is of any relevance. – Geoffrey Thomas Apr 5 '18 at 23:15
  • My position is not expressing that it is always wrong to kill in self defence. My position is objectively if I have the techniques and control needed to stop violent behavior without killing I am obligated not to kill. This means I will hold a home invader for the police unlike the immoral souls who objectively LIE and say the attacker threatens their lives. The reason the attacker dies in my care would be an accidental occurred. I objectively mean accident as opposed to the liers who Allege the attacker slipped & fell into his knife to cut his jugular. There is a difference there. – Logikal Apr 6 '18 at 0:04

From a Kantian perspective, it is unacceptable to consider any person as a mere means, rather than as a participant in the community of decision makers ('the kingdom of ends').

Kant argues against all forms of murder or suicide, because at the point you are making the call, the autonomy of the dead person has not been fully expressed. In the case of murder you are violating the other person's will, and in the case of suicide you are under duress, and it is possible that your own future will would be different. In either case, you are treating the person being killed as a mere means to some end, rather than as another real being. You get something out of the murder (even if that is just a feeling) or you escape your own suffering (which is itself just a feeling).

At the same time, he finds the existence of soldiers acceptable. This implies the trade of the possible loss of one's own life for a clear increase others' safety is to some degree logical and honorable and can be made with a clear view of the future. Therefore, one can set conditions upon one's own survival, if it is done in a carefully considered manner. This same position has been used to defend the modern approach to medical ethics: It may be better that the doctor or family should make a call about survival based on an understanding of the patient's clear, considered (preferably expressed) will than that the patient should make it himself while in duress.

So, if you are part of a society that embraces a form of honor that makes this permissible, things become different. In cultures with conventions about violence and self-defense, almost all of them, attacking someone is implicitly agreeing that you might be killed. The victim is not obligated to question your mental state, and is free to defend himself.

But where the person takes no action and has no agreement with you, you should avoid killing them. It is in the nature of autonomy to make decisions about one's own behavior. In sacrificing oneself, one is making a decision, while in sacrificing the other, the potential victim is making no decision. So it is more natural to the notion of autonomy, and it makes the victim less of a mere end, to not kill, than to voluntarily die.


By ethical I take you to mean something in philosophy called normative ethics.

Unlike other subjects that might use the words moral or ethical interchangeably, in philosophy the terms are distinct.

Normative ethics is a field that evaluates moral claims. By moral claims I mean how a rational person ought to act. This is not subjective or opinionated. Other fields like psychology, rhetoric, etc do not take this approach. What makes something a moral claim. Well what I was taught was just like like propositions. These are claims that must be either true or false, but who wants to persuade with false claims? I would start with true propositions and relate them as any argument but adding THE OUGHT part to the argument tends to cause formal logic issues.

So you killing a random person would be immoral because of the following facts: the person desired to live up to that point before you ended his life, you ended his life without his consent to take his life and you ended his life without his knowledge you would do so.

The facts alone should be related to the conclusion. If so then the facts should justify why the act is immoral. This is similar in law where a murder is committed by the mob. However there is no victim body to be found. After certain amount of time someone gets indited for murder. The prosecution has to convince the jury how the muderr likely was committed by the defendant without absolute proof. This has already been do e before in law with a CONVICTION. The facts alone will lead jury members that the probability this murder happened is greater than not happening. We could say the same for O.J Simpson. The probability he did do it outweighs his actuall innocent verdict. I could say O.J. acted immorally without any reference to law. The facts alone assist in the conclusion and not emotion. The idea in normative ethics is to eliminate or reduce emotional responses.

It is improper to ask a general statement and then add specifics much later after someone has answered JUST so you can disqualify that particular answer. This patter repeats in reality so often people are confused. The way things ought to work is you spell out an entire scennario in sequence and then ask for a response KNOWING you will not be able to add or subtract to your original scenario. This also reduces your chances of making up stuff as you go and reduces the nonsense factor as well.


There is no universal answer to the question "Is it ethically wrong to kill an innocent person (or people) for the purpose of self-preservation?" The answer depends on which ethical framework you are using. As you point out Utilitarianism would ask which provides the greater utility. Whereas a Common Good ethical framework would ask which provides for the greatest common good? I can easily imagine cases where the preferable answer would go either way.

  • Do you know of an ethical framework whereby it is permissible in general? – Kenshin Mar 23 '18 at 14:14
  • The Thuggee believed that by killing less "worthy" people they were preventing Khali from killing all humans. On the other end, many Buddhists believe that all life is sacred and any killing, even for self-preservation is wrong. There are many more examples of both if you are willing to do a little digging. – Patrick O'Hara Mar 29 '18 at 15:06
  • Your answer does not consider the distinction between the psychological desceiptive ethics and the philosophical study normative ethics. The two are not the same as psychology is distinct from philosophy. – Logikal Apr 5 '18 at 20:28
  • True, though I do not see that it is relevant? As I said it depends on the ethical framework that one uses to evaluate such decisions. Are you implying that either normative of descriptive ethics would tend to support a right/wrong answer to the question is it wrong to kill an innocent person for the purpose of self-preservation? – Patrick O'Hara Apr 13 '18 at 21:11

In American constitutional law, not being killed unjustly is a right that is acknowledged in the Declaration of Independence and laid out specifically by the Due Process Clauses that appear in the 5th and 14th Amendment:

...nor [shall any person] be deprived of life, liberty, or property, without due process of law (5th Amendment)

...nor shall any state deprive any person of life, liberty, or property, without due process of law (14th Amendment)

Killing a person in self-defense is the subject of "stand your ground" laws that have not failed constitutional scrutiny as of this writing (spring 2018). So American legal scholars find ethical grounds for this form of killing, when a person saw the dead person as a threat, completely in absence of a proper evaluation by a judge, jury, policeman, etc.

Another way of talking about this ethical situation has been named "trolley problem", in reference to a popular thought problem:

There is a runaway trolley barreling down the railway tracks. Ahead, on the tracks, there are five people tied up and unable to move. The trolley is headed straight for them. You are standing some distance off in the train yard, next to a lever. If you pull this lever, the trolley will switch to a different set of tracks. However, you notice that there is one person tied up on the side track. You have two options:

1.Do nothing, and the trolley kills the five people on the main track.

2.Pull the lever, diverting the trolley onto the side track where it will kill one person.

Which is the most ethical choice?

I won't attempt to analyze this problem here, except to say that there is by no means agreement by scholars that choosing to throw the switch is unethical.

Your question seems touched by both "stand your ground" cases and "trolley problem" cases, because the dead person wasn't by any means intending to be a threat to you. I think one applicable ethical theory is the Golden Rule:

Do unto others what you would have them do unto you.

So by this rule, given the choice, it is more ethical to choose self-death than to endanger another person.

  • The problem with your solution is that law is not equivalent to normative ethics. Appealing to the law for an act that is not FORCED upon you is a xop-out. This implies you have no true legit reasons for killing other than some authority said you could do it. To you the authority makes the act moral which is not addressed in your answer. – Logikal Apr 5 '18 at 20:25

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