Two Wrongs Make a Right





Two Wrongs Make a Right is a fallacy in which person A attempts to justify an action against person B by asserting that B would do the same thing to them, when the action is not necessary to prevent B from doing X to A. This fallacy has the following pattern:


Premise 1:  Person B would do X to person A.

Premise 2: A’s doing X to B is not necessary to prevent B from doing X to A.

Conclusion: It is acceptable for person A to do X to person B


This reasoning is fallacious because even if B would do X to A, it does not follow from this that it is acceptable for A to do X to B.

In general, it would not be wrong for A to do X to B if X is done to prevent B from doing X to A or if X is done in justified retribution. For example, if Biff attacks Sally while she is out for a run, Sally would be justified in attacking Biff to defend herself.

A variant of this fallacy is Two Bad. It has the following pattern:


Premises 1: A did X, which is bad.

Premise 2: B has also done X.

Conclusion: A doing X was not bad.




Premises 1: A did X to B, which is bad.

Premise 2: B has also done X.

Conclusion: A doing X to B was not bad.


This reasoning is fallacious because it does not follow that something bad is not bad because someone else has also done the bad thing. Many legal systems recognize that this is fallacy; doing something illegal because someone else did something illegal does not (usually) transform the illegal into the legal. For example, if Sally breaks Ted’s window with a rock, this does not make it good or legal for Ted to throw a rock through Sally’s window. But, of course, things can get complicated. Reasoning about self-defense, retribution, revenge, and retaliation would quickly move away from “pure” logic into the realm of moral reasoning (and legal reasoning).

This fallacy can be self-inflicted or used against others. When self-inflicted, it can often be used in conjunction with Rationalization. When used against others, it is often combined with fallacies such as Appeal to Fear and Appeal to Spite.


Defense: To avoid this fallacy, the main defense is remembering that even if a person would do wrong to someone else, it does not follow that it would be acceptable to do wrong to them. For the Two Bad fallacy, the defense is remembering that the wrongdoing of one does not automatically transform the wrongdoing of another into not being wrong. That said, you will need to consider if the situation is one of self defense or if the matter has been complicated by other aspects of moral (or legal) reasoning.


Example #1:

Bill: “Can I borrow your pen, Jane.”

Jane: “Well…it was a gift and is quite expensive…”

Bill: “I just need to sign this form.”

Jane: “Okay.”

Hugh: “Jane, can you come to my office?”

Jane: “Yes.”

Bill: “Hmm, I never gave her pen back. But she has a bad attitude, and I am sure she would have taken my pen. So free pen for me!”


Example #2:

Jane: “Did you hear about those terrorists killing those poor people? That sort of killing is just wrong.”

Sue: “Those terrorists are justified. After all, their land was taken from them. It is morally right for them to do what they do.”

Jane: “Even when they blow up busloads of children?”

Sue: “Yes.”


Example #3:

Jill: “Huh, the store undercharged me. That video card was supposed to be $399, but they just charged be $39. I should go back and pay the right price.”

Larry: “Don’t do that. If they overcharged you and you didn’t catch it, it is not like they would send you a check.”

Jill: “Well, I guess you are right.”


Example #4:

Jill: “Capital punishment is awful.”

Bill: “I must disagree. Capital punishment is harsh, but just.”

Jill: “It is just murder by the state.”

Bill: “Look, the state is killing people who didn’t have any qualms about killing other people. So, it is justice. Final justice.”

Originally appeared on A Philosopher’s Blog Read More