How does affirming the consequent produce an invalid conclusion?

Affirming the consequent is a fallacy because it incorrectly assumes that the truth of a conditional statement's result (the consequent) guarantees the truth of its condition (the antecedent).1

In a conditional "if-then" statement, the "if" part is the antecedent and the "then" part is the consequent. While a valid argument like modus ponens affirms the antecedent to prove the consequent, affirming the consequent reverses this logic.1

The conclusion is invalid because it is possible for the premises to be true while the conclusion remains false. For example:1
* Premise 1: If it rains, the game is cancelled.
* Premise 2: The game is cancelled.
* Invalid Conclusion: Therefore, it has rained.2

This conclusion is logically flawed because the game could have been cancelled for other reasons, such as a power outage or a scheduling conflict. Because the structure of the argument does not guarantee that the conclusion must follow from the premises, the inference is logically unsound.1