# Affirmation of the consequent – Definition & Meaning

Conclusion

In logic, affirmation of the consequent is a fallacy that occurs when someone assumes that if a statement is true, then its consequent must also be true. This fallacy is also known as the converse error. In this article, we will explore the definition and meaning of affirmation of the consequent.

## Definitions

Affirmation of the consequent is a logical fallacy that occurs when someone assumes that if a statement is true, then its consequent must also be true. It is a type of formal fallacy that occurs in deductive reasoning. In simpler terms, it is the mistake of assuming that if A implies B, and B is true, then A must also be true.

## Origin

The concept of affirmation of the consequent has been present in logic and philosophy for centuries. The term itself was coined by the philosopher John Stuart Mill in the mid-19th century. However, the fallacy has been recognized and discussed by philosophers and logicians for much longer than that.

## Meaning in different dictionaries

According to Merriam-Webster, affirmation of the consequent is “a logical fallacy that consists in inferring the truth of a proposition from the fact that its consequent is true when the truth of the proposition is not necessarily implied by the truth of the consequent.”
The Oxford English Dictionary defines affirmation of the consequent as “the fallacy of assuming that if a proposition implies a consequent, then the truth of the consequent implies the truth of the proposition.”

## Associations

Affirmation of the consequent is often associated with deductive reasoning and logical fallacies. It is a common mistake that people make when they assume that a statement is true simply because its consequent is true.

## Synonyms

Some synonyms of affirmation of the consequent include:

• Converse error.
• Fallacy of the converse.
• Fallacy of the consequent.
• False implication.

## Antonyms

There are no direct antonyms of affirmation of the consequent, as it is a logical fallacy rather than a valid form of reasoning. However, some related concepts include:

• Modus ponens (valid deductive reasoning).
• Modus tollens (valid deductive reasoning).
• Denying the antecedent (another logical fallacy).

## The same root words

The term “consequent” in affirmation of the consequent comes from the Latin word “consequens,” which means “following after.” The term “affirmation” refers to the act of asserting or stating something as true.

## Example Sentences

Here are some examples of affirmation of the consequent:

• If it’s raining, the streets will be wet. The streets are wet, so it must be raining. (This is a fallacy, as the streets could be wet for other reasons besides rain.).
• If you study hard, you’ll get good grades. You got good grades, so you must have studied hard. (This is also a fallacy, as there could be other reasons why someone got good grades besides studying hard.).

Affirmation of the consequent is a logical fallacy that occurs when someone assumes that if a statement is true, then its consequent must also be true. It is a common mistake that people make in deductive reasoning. By understanding this fallacy, we can avoid making the same mistake in our own thinking and arguments.