Two wrongs make a right

Over the fence

Every fall, the neighbors’ maple drops leaves all over Chris’s lawn, and they’ve never offered to help rake. This year Chris dumps his grass clippings over the fence into their yard. When they complain, he says: “Your leaves have been landing on my lawn for years.”

The neighbors’ leaves may be a real annoyance, but they don’t make dumping clippings acceptable. The clippings don’t clear a single leaf from Chris’s lawn, and there were obvious better options, like asking the neighbors to help. This is the clear-cut case. Ralph Johnson and J. Anthony Blair describe the fallacy as an attempt to “elevate the instinct to retaliate into an argument” (as quoted by S. K. Wertz), and that’s all Chris’s reply does.

Answering criticism with the critic’s record

Sam: You haven’t taken the trash out all week. It’s starting to smell.

Alex: You left dishes in the sink for four days last week, so don’t lecture me.

Alex’s reply does two things at once. As a reason to ignore Sam’s point, it’s tu quoque: the dishes don’t change whether the trash smells. As a defense of skipping the trash, it’s two wrongs: Sam’s dishes don’t make Alex’s week acceptable. Sam’s dishes may well deserve their own conversation. They just aren’t an answer to this one.

“It evens out”

In a board game league, Priya’s opponent miscounted his score in his own favor earlier in the evening, and nobody caught it at the time. In the last game, Priya notices that the scorekeeper has added three points to her total by mistake. She says nothing. “He got extra points earlier. This just evens it out.”

This one sounds like fairness, which is why it’s persuasive. Johnson and Blair observe (again as quoted by Wertz) that such arguments seem plausible because they appeal to our sense of justice and fair play. But Priya’s silence doesn’t correct the first mistake; it adds a second one, and the result is only “even” by accident. If the earlier miscount matters, the fix is to raise it with the scorekeeper, not to keep a second error quietly.

• Retaliation: “they did it to me first.”
• Pointing at the critic: answering a criticism with the critic’s own similar wrong. This is where two wrongs and tu quoque overlap.
• Common practice (“many wrongs make a right”): “everyone does it, so it’s fine.” Howard Kahane treated two wrongs as a variation of this fallacy; it’s covered as a form of Appeal to popularity.
• Mitigation: using the other wrong not to justify the action but to reduce the blame for it. Johnson and Blair count this as a weaker variant of the fallacy. Groarke disagrees in part: being provoked over a long period, he argues, really can lessen how much someone is to blame.

Where does it belong? References disagree. S. K. Wertz traces the fallacy in the informal logic literature to Howard Kahane, who introduced it in 1969 as the tu quoque (“if they can do it, so can we”). According to Wertz, Douglas Walton treats it as a variation of the circumstantial Ad hominem, and Trudy Govier as a misuse of argument from analogy. Bradley Dowden’s list in the Internet Encyclopedia of Philosophy calls it a special kind of ad hominem. Johnson and Blair’s Logical Self-Defense treats it as a fallacy in its own right (Wertz notes they analyze it alongside analogy and common practice), and the Stanford Encyclopedia of Philosophy names “two wrongs” among the fallacies their list added to the traditional ones. This site keeps it separate from ad hominem because it defends an action rather than rejecting a claim.

A previous wrong sometimes does change what’s right to do. Groarke gives self-defense, lying to someone who is hunting for an intended murder victim, and justified punishment as examples. The Stanford Encyclopedia of Philosophy entry on informal logic lists two wrongs reasoning among the traditional fallacies that can play a legitimate role in real reasoning. Groarke, later with Christopher Tindale and Linda Fisher, set out conditions for when it does (as summarized by Wertz):

• It responds to the earlier wrong. The action is aimed at canceling or alleviating the harm that wrong causes, not just at getting even.
• It isn’t worse than what it responds to. Force used in self-defense has to stop when the attack stops.
• There’s no morally better response available. If asking, reporting or walking away would work as well, the second wrong isn’t justified.

Separately, an earlier wrong can mitigate without justifying. Groarke argues that someone who lashes out after being provoked for a long time is less to blame than someone who wasn’t, even if what they did still wasn’t acceptable. Saying so isn’t a fallacy, as long as it isn’t presented as showing the act was fine.

Groarke notes that deciding which responses are “morally preferable” is a question for ethics, not logic, so applying these conditions takes judgment. The test: does the action do something about the other wrong, with nothing better available, or does it just point at it?

Pulling your bag back

On a crowded train platform, a man grabs Jamie’s bag and starts to run. Jamie holds on and yanks it back hard, and the man stumbles and falls. Later a bystander says Jamie could have hurt him. Jamie says: “He was stealing my bag.”

Knocking someone over would normally be wrong, and Jamie’s defense points to the other man’s wrong. But the pull was a direct response that stopped the theft, it went no further than needed, and there was no time for a better option. If Jamie had chased the man down and hit him after he dropped the bag, the same defense would fail. This meets the responds to, not worse and no better response conditions.

Keeping part of the deposit

A landlord returns a tenant’s security deposit minus $300, with receipts showing that’s what it cost to repair a door the tenant broke. The tenant says keeping someone else’s money is wrong.

Keeping money that belongs to someone else would ordinarily be wrong. Here the deduction responds to the damage, matches the cost of repairing it, and follows a procedure both sides agreed to in the lease. The justification is a principle about repairing harm, not “you did something wrong, so I can too.” If the landlord had kept the whole deposit for a $300 repair, that would no longer be justified.

Johnson and Blair, in the passages Wertz quotes, suggest two reasons. It starts from an instinct: when someone wrongs us, the urge to strike back is strong, and “they did it first” dresses that urge up as a reason. And it borrows from real arguments: fairness, self-defense and punishment are genuine moral ideas, so a two wrongs defense can sound like one of them. Where it goes wrong, in their account, is by misapplying those principles of justice, or by resting on unwarranted assumptions.

It’s also often true that the other person did something wrong, so the reply lands on a real point. The mistake is treating that point as if it answered a different question: not whether they were wrong, but whether you were.

• Separate the two questions. Was the other thing wrong? Was this action wrong? A yes to the first doesn’t settle the second, and it’s fine to agree that both deserve attention.
• Ask what the action does about the other wrong. Does it repair or prevent harm, or only match it?
• Ask what else was possible. Many two wrongs defenses fail because a better response was available.
• When you’ve been wronged yourself, look for the response that fixes the problem, not the one that evens the score. That’s also the one that will hold up if someone questions it.