​Slippery slope

A fallacy is the use of faulty reasoning in an argument.

There are formal and informal fallacies:

• A formal fallacy describes a flaw in the construction of a deductive argument.
• An informal fallacy describes an error in reasoning.

If-by-whiskey is a fallacy named after a speech given in 1952 by Noah S. Sweat Jr. It is used to conceal a lack of a position or to dodge a tough question. 

If, by whiskey, you mean the brew that causes so many problems, then I'm against it. But if whiskey means the oil of convers...

In this fallacy, when someone doesn't have a strong argument, they will sprout irrelevant facts, numbers, anecdotes and other information to confuse the issue.

It happens when someone continues in a course of action, even if evidence shows that it's a mistake.

Common phrase: "We've always done it this way, so we'll keep doing it this way." "I've already invested so much..."

This is a common fallacious rhetorical strategy that is difficult to spot.

It occurs when someone's claim is threatened with counter-evidence. They then come up with a rationale to dismiss the counter-evidence in the hope to protect their original claim.

This fallacy argues for a specific position because there are no other realistic alternatives.
Common phrase: "What else are we going to do?"

In this fallacy, someone behaves in a way that negatively affects others but then gets upset when others criticize their behavior. They will reply with a "mind your own business."
For instance, someone who doesn't see a reason to bathe, but then boards a full 10-hour flight.