Non Sequitur (Latin for "it does not follow") is a logical fallacy that occurs when a conclusion is drawn that has no logical connection to the premises offered in support of it. As a formal fallacy, the error lies in the structure of the argument itself rather than in the truth or falsity of its content. This makes Non Sequitur one of the most fundamental reasoning errors, because even when every stated premise is perfectly true, the conclusion can still be completely unwarranted if the logical link between premises and conclusion is broken or absent.
Non Sequitur arguments work—and fool people—because the human mind is naturally inclined to find patterns and connections, even where none exist. When a speaker states premises confidently and then delivers a conclusion with equal confidence, listeners often assume that a valid logical bridge exists between them. This tendency is amplified when the premises and the conclusion are individually plausible or emotionally appealing; people may not pause to examine whether the conclusion actually follows from the specific evidence presented. Political rhetoric and advertising frequently exploit this gap, stringing together agreeable statements before slipping in an unrelated conclusion.
A famous historical example can be found in critiques of Cold War-era reasoning. Some arguments took the form: "The Soviet Union is a powerful nation; the Soviet Union has nuclear weapons; therefore, communism is a superior economic system." While the premises may have been factually accurate, the conclusion about economic superiority does not logically follow from military capability. Aristotle was among the first to formally categorize such reasoning errors in his Prior Analytics and Sophistical Refutations, laying the groundwork for identifying Non Sequitur as a violation of valid syllogistic form.
To recognize a Non Sequitur, ask yourself: "If I accept every premise as true, does the conclusion necessarily or even probably follow?" If you can imagine a scenario in which all the premises hold but the conclusion is false, the argument commits a Non Sequitur. Countering it is straightforward: identify the logical gap explicitly, and request the speaker to explain the missing step that supposedly connects the premises to the conclusion. Often, no such step exists.
