Argument from Fallacy
The argument from fallacy occurs when one concludes that a claim is false because the argument supporting it is fallacious. Truth and falsity are features of claims, not reasoning, so a fallacious argument does not guarantee a false conclusion.
THE IDEA
Argument from Fallacy
Also known as: argumentum ad logicam, argument to logic, disproof by fallacy, fallacy fallacy, fallacist’s fallacy, bad reasons fallacy (as a form), psychogenetic fallacy (as a form).
Description
The argument from fallacy occurs when one reasons that because an argument contains a fallacy, the conclusion of that argument is false. Truth and falsity are features of claims, not of reasoning. Fallacies are errors in reasoning; an argument can be fallacious yet lead to a true conclusion. Conflating the quality of an argument with the truth‑value of its conclusion is itself an error in reasoning – hence the name “fallacy fallacy.”
Logical Form
- Argument A for claim C commits a fallacy (or is otherwise weak).
- Therefore, claim C is false.
The premise identifies a flaw in the reasoning. It does not establish that the claim is false.
Examples
Example 1 (Affirming the Consequent)
- If Atlanta is the capital of Georgia, then it is in the United States.
- Atlanta is in the United States.
- Therefore, Atlanta is the capital of Georgia.
This argument is an instance of affirming the consequent and is deductively invalid – but the conclusion is true. Responding, “Because that argument is fallacious, Atlanta is not the capital of Georgia,” would be an argument from fallacy.
Example 2 (Ad Hominem / Dismissing the Claim)
Sidney: “Ivan is an idiot, so his car won’t turn into a pumpkin at midnight.” Observer: “Sidney just used an ad hominem fallacy. That means Ivan’s car actually will turn into a pumpkin!”
Calling Ivan an idiot provides no support for Sidney’s claim about the car. It also provides no reason to believe the opposite claim.
Example 3 (Slippery Slope)
Brad: “We cannot allow same‑sex marriage. If we do, next we’ll have to allow people to marry their parents, their pets, even monkeys. Where do we draw the line?” Janet: “That’s the slippery slope fallacy! Therefore, you’re wrong – we should allow same‑sex marriage.”
Janet correctly identifies Brad’s poor reasoning, but she then commits the argument from fallacy. The fact that Brad’s argument is fallacious does not prove that his conclusion is false. The conclusion (whether same‑sex marriage should be allowed) must be debated on its own grounds.
Example 4 (Post Hoc)
Jon: “I prayed every night for a week to get this gig, and last night I got the message that we got it. Prayer works!” Richie: “That’s the post hoc fallacy. So prayer doesn’t work.”
Richie rightly points out that assuming causation just because one event follows another is fallacious. That criticism alone does not settle whether prayer has the claimed effect. Jumping from “the argument is fallacious” to “prayer is ineffective” is the fallacy fallacy. (The question might also involve other issues, such as untestability, but that does not rescue Richie’s inference.)
What a Weak Argument Can Tell You
A weak argument may prompt us to ask whether the speaker has better evidence. This might lower our confidence in the arguer’s ability to provide good reasons, but it does not serve as direct evidence against the claim itself. The truth of the conclusion remains a separate matter.
Variations
- Bad reasons fallacy: A broader form in which the argument need not contain a formal logical fallacy; it may simply be weak or rely on poor evidence. The mistake is the same: concluding that a claim is false merely because the reasons offered for it are bad. A conclusion can be true even when supported by terrible reasons.
- Psychogenetic fallacy: Inferring that an argument is invalid (or its conclusion false) based on a psychological explanation of why the arguer is making it. For example, “You only argue that because of your upbringing, so your conclusion is false.” Like the argument from fallacy, it confuses the origin of an argument with its truth value.
How to Avoid the Fallacy
When you identify a fallacy, explain what the argument fails to establish. Then assess the claim using other reasons and evidence. The aim is to evaluate the claim, rather than simply “defeat” the person presenting it.
When to use it
In a debate, pointing out a logical flaw does not automatically disprove the opponent's conclusion.
When reading news articles, remember that a poorly argued point may still be correct.
In academic writing, avoid concluding that a claim is false just because the evidence provided is weak.
When analyzing political speeches, separate the strength of the argument from the truth of the claim.
When someone identifies a fallacy in your argument, reconsider the support for your claim and look for better evidence.
When moderating an online discussion, ask participants to explain what an alleged fallacy does and does not establish.
When reviewing academic work, distinguish a conclusion that lacks adequate support from one contradicted by the evidence.
FROM THEORY TO EVERYDAY LIFE
In practice
Sidney and Ivan
Sidney calls Ivan an idiot and concludes that Ivan’s car will not turn into a pumpkin at midnight. The insult does not support that conclusion. It also does not support the opposite conclusion that the car will transform.
Karen's Argument
Suppose Karen claims that humans rode dinosaurs and supports the claim by insulting her critics. Her insult does not establish her claim, but identifying the insult does not refute it either. Evidence about human and dinosaur history addresses the claim itself.
Brad and Janet on Same-Sex Marriage
BRAD: Dammit, Janet! We simply cannot allow same‐sex marriage. If we allow same‐sex couples to marry, then the next thing you know we’ll have to allow people to marry their parents, their pets, even monkeys. I mean, where do we draw the line? JANET: Oh, Brad! That’s the slippery slope fallacy, and you can’t use fallacious reasoning to support an argument. So, see, you’re wrong that we shouldn’t allow same‐sex marriage.
Jon and Richie on Prayer
JON: Look, man, I’m telling you: I prayed for this gig to open up for us – every night for a week – and when I checked my messages last night, there was one that said we got the gig! It worked, man! RICHIE: Dude, saying that you prayed for something and it then happened, so it must have happened because you prayed for it, is a fallacy called the post hoc fallacy. That means prayer doesn’t work.
A MOMENT TO REFLECT
Put it to work.
When you identify a fallacy, what exactly have you shown about the argument? What remains to be established about its conclusion?
Think of a time when you dismissed a claim because the argument for it was flawed, but the claim might still be true.
What is the difference between a fallacious argument and a false conclusion?
How could someone replace a flawed argument for a claim with a stronger one? Would you assess the new argument differently?
Could the same flawed reasoning support a true conclusion in one example and a false conclusion in another?
How would you respond if someone treated your criticism of their reasoning as a rejection of their conclusion?
CONTINUE THE CONVERSATION
Source texts
- Bad Arguments 100 of the Most Important Fallacies in Western Philosophy (Steven Barbone, Michael Bruce)
- Logically Fallacious - The Ultimate Collection of Over 300 Logical Fallacies