What is defined as a failure of reasoning?

A failure of reasoning is best defined as a logical fallacy. Logical fallacies occur when an argument is based on flawed logic or reasoning, which undermines its validity. These fallacies can take various forms, such as appealing to emotions rather than facts, making unjustified assumptions, or drawing conclusions that do not logically follow from the premises.

In contrast, an argument refers to a statement or series of statements intended to convince someone of something; it doesn’t inherently include flawed reasoning. A fact is an objective reality that can be proven true or false, and a theory is an established explanation based on evidence that is subject to change as new information becomes available. Neither a fact nor a theory describes a failure of reasoning, making logical fallacy the correct choice in this context, as it directly relates to flawed reasoning in argumentative discourse.