Ad Hominem

Ad hominem (argumentum ad hominem) is a type of informal logical fallacy. It is typically carried out not by responding to a proposition or argument, but by attacking the person making the proposition—their character, attitudes, or previously expressed views—in order to divert attention from the issue at hand. The structure of the ad hominem fallacy is as follows:

1. a presents argument α.
2. a is personally a bad person.
3. Therefore, argument α should not be accepted.

This form of counterargument does not address the content of argument α.

History

Ad hominem fallacies appear in the texts of Aristotle from antiquity^【1】. They were revisited in the 17th century by John Locke^【2】. During the 18th century, Locke’s classification remained largely valid, and in the 19th century, thinkers such as Richard Whately and Arthur Schopenhauer revisited them. The term ad hominem was formalized during these periods.

Philosopher Busts (Pixabay)

Etimology

The Latin term argumentum ad hominem means “argument directed at the person.” It has been termed the “character assassination fallacy” by Alev Alatlı^【3】.

Types of Ad Hominem

Ad hominem can be divided into several main types: circumstantial ad hominem, tu quoque, abusive ad hominem, and poisoning the well.

Circumstantial Ad Hominem

Circumstantial ad hominem is a fallacy in which a person responds not to the argument itself, but to the opponent’s circumstances in relation to the argument^【4】. This can be explained by the following schema^【5】:

1. a defends argument α, which concludes with proposition A.
2. a has previously engaged in an action implying adherence to a proposition that is not A (A’).
3. Therefore, a is a hypocritical or bad person.
4. Therefore, a’s argument α should not be accepted.

Example: My doctor told me that drinking too much coffee is harmful to health. But I saw him drinking coffee the other day, so coffee must not be harmful after all.

Tu Quoque Fallacy

The tu quoque fallacy is defined as diverting the issue by highlighting an inconsistency in the opponent’s behavior related to the argument, rather than addressing the argument itself.

Example: — We should not kill animals for food. — How can you say that when you have steak on your plate?

Poisoning the Well

Poisoning the well is a fallacy in which one party in a debate attempts to preemptively discredit the other party’s arguments by casting doubt on their credibility before they even present them.

At its core, this fallacy aims to invalidate a person’s right to speak on a subject based on general characteristics such as their social status, past behavior, or group affiliation. Although this type of argument does not involve direct personal attack, it seeks to illegitimately exclude the opponent from the debate by asserting their lack of competence to speak on the subject, thereby creating a “silencing” effect^【6】. For example, claiming that a man cannot speak on abortion solely because he is male, or dismissing an academic’s views on military strategy because he never served in the military, are examples of this fallacy^【7】.