Have you ever heard the word “fallacy?”

A fallacy is the use of wrong moves in the construction of an argument — when you’re trying to convince someone of something. These wrong moves render your argument unsound.

There are dozens of types of fallacies.

Some fallacies are committed
1) intentionally to manipulate or persuade by deception, while others are committed
2) unintentionally due to carelessness or ignorance.

Personally, the fallacy which makes me cringe is the Ad Hominem (“against the person”) — it falls into group #1. It’s also called “The Fallacy of Personal Attack.” Ad Hominem is the most familiar logical fallacy of them all, and I’ve seen it used by people as a tool to deceive their audience. In my opinion, using an Ad Hominem argument is a sign of desperation used by desperate people.

Ad Hominem arguments can take the form of attacking somebody or casting doubt on his character in order to discredit the person making the argument. The result of an Ad Hominem argument can be to undermine someone’s case without actually addressing it.

The Ad Hominem fallacy involves two steps. First, an attack is made against the character of the person making the claim. Second, this attack is taken to be evidence against the claim which the person in question is making. The Ad Hominem argument looks like this:

Person A makes claim XYZ.
Person B makes an attack on person A.
Therefore, Person A’s claim XYZ is false.

Example of an argument where an Ad Hominem fallacy is used:

Jane: “I believe that the county should require cats to be registered and vaccinated against rabies.”
Jack: “Why should we listen to you — you’re a chronic liar.”
Jane: “What about the arguments I gave to support my position?”
Jack: “Like I said, you always lie. Furthermore, you’re a crook, and you want the state to control everything. Next, you’re going to want to have my parakeet vaccinated.”

The Ad Hominem argument leaves an impression on the mind which is hard to spot. Although the personal attack that has been made on the opponent might not have any truth in it, it somehow makes the audience biased and has the power of persuasion. Once an Ad Hominem is used against someone, it smears his reputation — the audience, instead of evaluating it on logical grounds, takes it to be true.

Donald Trump is quite practiced in the Ad Hominem argument. Senator Marco Rubio’s height is irrelevant to anything political and Trump’s tweet “Truly weird Senator Rand Paul of Kentucky reminds me of a spoiled brat without a properly functioning brain. He was terrible at DEBATE!” is classic Ad Hominem.

Learn to recognize the Ad Hominem fallacy and call out the person making it. Evaluate arguments on the basis of merit, not on personal attacks made by desperate people.