Common Logical Fallacies and Argumentative Structures

Types of Arguments and Fallacies

Argument from Authority (Ad Verecundiam)

This argument relies on the credibility of a person of authority. When constructing a lengthy argument, it is often difficult or impossible to justify every assumption made. The Fallacy of Authority occurs when the mention of authority is used to suppress critical response.

Ad Baculum Argument (Appeal to Force)

This argument uses threats, intimidation, advice, or instructions as if they constituted a sound reason for accepting a conclusion. If threats are used to compel acceptance, the argument commits the Ad Baculum fallacy. If the threat is empty, the argument is weak or bad.

A common example is when politicians attempt to frighten the public by predicting various tragedies related to voting choices, implying extreme damage if their advice is not followed.

Ad Populum Argument (Appeal to Popularity)

This argument attempts to gain approval from the audience by appealing to their desires for belonging or acceptance, often without providing evidence. Advertising commercials, for instance, frequently relate products to widely accepted feelings or popular trends to achieve product awareness. [7]

Ex Populo Argument (The Bandwagon Fallacy)

This argument asserts that a claim is true because "the whole world agrees with this."

The schema for this argument is:

1. The world supports P (or does not support P).
2. Therefore, P is true (or P is false).

These schemas are not valid deductions, but the consensus of the people often holds the power to convince. If the whole world believes P is true, but someone claims the contrary, that person is often accused of lying to demonstrate P.

Post Hoc Ergo Propter Hoc Argument

This phrase means: "After this, therefore because of this." This is also known as the False Cause fallacy. It assumes that because event A occurred before event B, A must be the cause of B.

The structure is:

Event A occurred, and then Event B occurred. Therefore, A caused B.

The mere temporal occurrence of A and B is insufficient to establish a causal link. This kind of reasoning is the source of many superstitious arguments. For example, a person drinks a specific refreshing beverage before a sports competition and subsequently wins. They then attribute the win to the drink, believing it possesses magical qualities.

This argument is flawed because the cause-effect relationship is not based on solid empirical evidence.

Slippery Slope Argument

This argument is based on the domino effect. It asserts that a relatively small first step (A1) will inevitably lead to a chain of related, increasingly negative events (A2, A3... An), culminating in a disastrous outcome (An).

The structure is:

1. If A1 occurs, then A2 will inevitably follow.
2. If A2 occurs, then A3 will inevitably follow...
3. ...leading eventually to An.
4. An is an undesirable outcome.

Therefore, A1 must not be allowed to occur.

Analyzing the likelihood of this chain of events is essential when evaluating this argumentative strategy. [8]