This fallacy occurs when an (alleged) wicked motive is taken as proof that a claim is untrue, or an argument is flawed. It is the “reverse” of Noble Motive. This reasoning has the following general form:
Premise 1: Person P makes claim C or argument A.
Premise 2: Person P’s motivation for making C is (alleged to be) wicked.
Conclusion: Claim C is false, or argument A is flawed.
While motives are relevant in normative assessment (such as in law and morality), they are irrelevant to the truth of a claim or the quality of an argument. A person can make a true claim or a good argument, even if they have a wicked motive for doing so. For example, someone might reveal another person’s secret because they want to hurt and embarrass that person. But their motive does not make their claim untrue.
The following example illustrates why this is a fallacy:
Premise 1: Sally tells Sam that deer ticks carry Lyme disease.
Premise 2: Sally’s motive is to torment Sam, a hypochondriac who has found a tick on his skin.
Conclusion: Therefore, deer ticks do not carry Lyme disease.
While Sally should, perhaps, be condemned for tormenting Sam, her wicked motive does not disprove the fact that deer ticks can carry Lyme disease.
In some cases, this fallacy gains its psychological force because the (alleged) wicked motive causes a feeling of dislike that can influence the target audience of the fallacy. The target audience can be the person committing the fallacy; it can be self-inflicted or targeted at others. For example, Democrat who thinks that a Republican is supporting a bill out of a racist motive might commit this fallacy.
The fallacy can also occur when the wicked motive undermines the person’s credibility. While considering factors that undermine credibility is not fallacious, inferring that a person whose credibility has been undermined must be wrong would be. For example, imagine a couple involved in a bitter divorce. One spouse might reveal a secret about the other to hurt and embarrass them, which would be a wicked motive. With such animosity in play, it would be reasonable to be skeptical of the spouse’s claim, they do have a reason to say untrue things. But it does not follow that they are lying.
This fallacy can be made in good and bad faith. There are two ways to commit this fallacy in bad faith. The first is that the person is using the fallacy intentionally. The second is that the person is lying about the wicked motive. But lying is not required for this to be a fallacy. The logical error is not lying but the inference from motive to truth or quality of argument.
When made in good faith, the person committing the fallacy believes their target is acting from a wicked motive and they are unaware of this fallacy. But, of course, they would still be committing this fallacy.
Defense: The defense against this fallacy is to remember that a person’s motives are irrelevant to the truth of their claims or the quality of their argument. Motives are often relevant to normative assessment, such as in law and ethics. But this sort of assessment goes far beyond “pure” logic. Motives are also relevant in assessing credibility, so it is reasonable to take them into account when assessing a claim. Because of this, it is wise to be careful to distinguish between reasonable assessment of credibility and this fallacy. For example, a lawyer who claims that a witness has wicked motives to undermine their credibility would not commit this fallacy. Unless they concluded that the witness’ claim must be false because of this alleged wicked motive.
It is also reasonable to consider whether the allegation of wicked motives is true, although the fallacy occurs whether the allegation is true or false. Exposing the allegation as false can sometimes help reduce the psychological force of the fallacy.
This fallacy can be self-inflicted, so it is wise to be on guard against it especially when judging someone you think has wicked motives, such as someone whose politics or ethics you dislike. The fallacy can also be inflicted by someone else on you, so you will want to be on guard against that as well.
“The Democrats claim that Judge Smith is unfit for the Supreme Court because of his alleged history of sexual assault. But we all know that the Democrats hate this man and just want to steal a seat on the court from our President with their lies.”
“The Republicans claim that Judge Smith is unfit for the Supreme Court because of his alleged history of sexual assault. But we all know that the Republicans hate this man and just want to steal a seat on the court from our President with their lies.”
Kelly: “Wow, did you hear what that famous actor said about her husband? She claims he abused her for years. That is why she has filed for divorce.”
Sally: “Yeah. She is just trying to make him look bad so the judge will award her more money. She hasn’t had a good job in years, and he has been bringing in all the money. Also, she is probably also jealous of him.”
Kelly: “Well, she does have a reason to lie…”
Sally: “Yup. So, she is definitely lying.”
“These green energy fools hate capitalism and hard work. That is why they claim wind and solar should replace coal and oil. All their talk about the alleged benefits of renewable energy is driven by this hate, so they are lying. Lying to try to destroy America.”
“These fossil fuel energy fools hate the environment and poor people. That is why they claim coal and oil are still needed. All their talk about needing them is driven by this hate, so they are lying. Lying to try to destroy America.”