This research focuses on explaining the history of the emergence of (Skepticism) that denies knowledge and rejects all facts. The research attempts to uncover the reasons for the emergence of doubt in ancient Greece and how it transformed into an intellectual doctrine. It also highlights the dangerous consequences of this doubt, which completely rejects knowledge and denies the moral values that regulate family and society. The research mentions the types of doctrinal doubt and divides them into main types and subtypes. It explains the concept of each type and highlights the logical fallacies associated with each type. The research relies on rational, logical, and philosophical arguments to criticize all types of doctrinal doubt and expose their cognitive mistakes.