Final answer:
The invalid form known as affirming the consequent has the pattern: If X, then Y. Y. Therefore, X.
Step-by-step explanation:
The invalid form known as affirming the consequent has the following pattern:
- If X, then Y.
- Y.
- Therefore, X.
In this form, the truth of the consequent (Y) is affirmed to infer the truth of the antecedent (X). However, this is an invalid inference because the truth of Y does not necessarily imply the truth of X.