Denying the antecedent is a logical fallacy  that occurs when, from a conditional statement,  

one incorrectly infers that if the antecedent  (the "if" part) is false, then the consequent  

(the "then" part) must also be false. This form  of reasoning is flawed because the consequent can  

still be true even if the antecedent is false. Everyday example:

Someone said "If I study hard, I will  pass the exam. I didn't study hard,  

so I will not pass the exam." This reasoning is fallacious  

because there are other ways to pass the exam  besides studying hard, such as already knowing  

the material or making educated guesses. The absence of studying doesn't necessarily  

guarantee a failure; it just negates  one specific path to success. 

This example demonstrates the error  in concluding that the failure of the  

condition (studying hard) automatically leads to  the failure of the outcome (passing the exam).