Logical Fallacies

What is a logical fallacy

A logical fallacy is an argument pattern where the conclusion sounds plausible, but the link between evidence and conclusion is weak or broken. A fallacy doesn’t automatically make the conclusion false — it just means there isn’t enough reason to accept it yet.

In critical thinking, we study fallacies not to attack other people, but to make our own judgments better.

Common fallacies

Fallacy	Structure	Example
Ad hominem	Attacking the person instead of the claim	”They’re too young to know what they’re talking about”
Straw man	Distorting the other side’s argument to knock it down	”So you’re saying welfare means unlimited taxes?”
Hasty generalization	Judging the whole from too few cases	”One employee was rude, so the whole company is bad”
Appeal to authority	Treating authority alone as proof	”A celebrity said it, so it must be true”
False dilemma	Reducing the options to only two	”You’re either for it or against us”

These fallacies show up in debates, advertising, political rhetoric, and work meetings alike.

A caution about spotting fallacies

Knowing a lot of fallacy names matters less than seeing the structure. Ask: “Does this evidence actually support this conclusion?” “Am I ruling out other possibilities too quickly?” “Am I mixing up judging the person with judging the claim?”

Also, pointing out fallacies should serve the purpose of the conversation. Slapping a fallacy name on every statement turns a discussion into a fight.

An example analysis

“That product was recommended by a popular YouTuber, so it must be good quality” risks an appeal to authority. To strengthen the argument, you’d need to check whether the YouTuber has real expertise in that area, whether there’s actual test data, and whether the video was sponsored.

Key takeaways

• A logical fallacy is an argument pattern where the link between evidence and conclusion is weak.
• A fallacy doesn’t automatically make the conclusion false.
• What matters more than naming fallacies is checking whether the evidence really supports the conclusion.
• Use fallacy-spotting to improve the conversation, not to score points.

Next chapter: cognitive biases — the habitual distortions in human judgment that go beyond pure logic.