No matter what terms you may put in the place of a, b, and c, if all a are members of the class called b, and c is a member of the class called a, the c must necessarily be a member of the class called b. Because there are only a small number of possible relationships between the terms, these relationships can also be represented by symbols. When this is done, the whole form of an argument can be written in symbols. This is called symbolic logic, which is a special branch of the study of formal validity. Informal Fallacies Correct reasoning involves clear expression and valid form.
Formal fallacies are a matter of invalid form.
Informal fallacies are a matter of unclear expression. Formal fallacies deal with the logic of the technical structure, while informal fallacies deal with the logic of the meaning of language. It only means that our focus is not on the form of the argument, but on the meaning of the argument. We encounter both formal and informal fallacies every day, but unlike formal fallacies, we cannot reduce informal fallacies to symbolic formulas. We can, however, compile a list of characteristic profiles of informal fallacies, and arrange them into general categories.