How can the structure of an argument create a formal fallacy?

A formal fallacy occurs when an argument violates the rules of formal logic due to its structure or form, rather than its content. In deductive reasoning, an argument is valid only if the truth of the premises guarantees the truth of the conclusion. A formal fallacy arises when the process of inference is improper, making it possible for the premises to be true while the conclusion is false.12

Common structural errors include:

• Conditional Fallacies: These involve misusing "if...then" propositions. Examples include denial of the antecedent and affirmation of the consequent, where the reasoner incorrectly assumes a specific direction of logical necessity.32
• Syllogistic Fallacies: These occur in syllogisms when rules regarding the "distribution" of terms are broken. For instance, the fallacy of the illicit major or minor premise happens when a term is distributed in the conclusion but was not distributed in the premises, overstepping the logical scope established by the argument's structure.3

Ultimately, these fallacies demonstrate that the validity of an argument depends entirely on its internal structure, independent of whether the statements are true in the real world.2