Affirming the consequent is a logical  fallacy involving an incorrect inference  

from a conditional statement. It occurs when one  reason that because the consequent (aka the "then"  

part of a conditional statement) is true, the  antecedent (aka the "if" part) must also be true. 

This reasoning is flawed because it ignores other  possible reasons for the consequent being true. 

Everyday example: Consider the statement:  

"If it is raining, the ground will be wet." An  instance of affirming the consequent would be:  

"The ground is wet, therefore it must be raining."  

This conclusion is fallacious because there  are other reasons the ground could be wet,  

such as a sprinkler system or a spilled bucket  of water. The wet ground doesn't necessarily  

mean it's raining; it's just consistent with  what would be the case if it were raining.