In simple terms, logic can be defined as the art and science of reasoning. Logic is broadly categorized into Formal and Informal Logic. While formal logic is primarily concerned with the validity of an argument, Informal logic examines the truth value and fallacies of the argument. Informal logic is also known as dialectical logic.
Informal logic deals with the words in order to examine the truth value and fallacies of the argument. For this reason, many symbols are not used in informal logic because changing the words will interrupt the study of the proposition.