Non sequitur

	Cogito ergo sum; Logic and rhetoric
	Key articles
	Logical fallacy; Syllogism; Argument;
	General logic
	Morton's fork; Certum est quia impossibile est; Definitional fallacies; Post hoc, ergo propter hoc (español); Lógica; Pensamento mágico;
	Bad logic
	Quidquid latine dictum sit, altum videtur; Good old days; Argument from omniscience; Appeal to ancient wisdom; Not an argument; Post hoc, ergo propter hoc (español); v - t - e

A fine example of a non sequitur argument. The premise (a cat pushes a watermelon out of a lake) is unlikely to have anything to do with the argument (assuming the debate isn't over whether a cat could push a watermelon out of a lake).

“”Non sequitur: when a train of thought proceeds from A to B and back again to Q.

—Bill Griffith, Zippy the Pinhead^{[note 1]}

Non sequitur is a Latin phrase meaning "it does not follow". It means that the conclusion reached does not follow from the premise(s). Oftentimes, examples of non sequitur arguments are hilariously disconnected, but those encountered in the wild can be subtle and may not be easily uncovered. The reason that such arguments are fallacious in logic should be fairly obvious.

Blatant examples[edit]

Examples of non sequitur arguments:

All men are mortal, and Socrates is a man, therefore Socrates likes women. (In which way?)
What's the difference between a duck? Three, because milk has no bones.
Morgan Freeman has cotton candy, I have a crab hat, and this baloney is smiling. Your argument is (in)valid.
If Chewbacca lives on Endor, you must acquit.

Men and machines[edit]

Non sequiturs can also be more subtle than the above, such as the following one, formulated by Alan Turing:

P1: If each man had a definite set of rules of conduct by which he regulated his life he would be no better than a machine.

P2: However, there are no such rules.

C: Therefore, men cannot be machines.

While this may seem plausible on the surface, it is still a non sequitur because 1) the first premise says nothing about whether or not men can be machines, but whether they would be better than (or, depending on how you unpack this term, greater than, more than, beyond, or simply more capable than) machines if they had definite rules of conduct by which they regulated their lives; 2) it ignores the possibility that men could be machines without such definite rules and 3) the second premise is saying something so strong that it is false. Therefore, the conclusion does not follow from the premises, nor would it be verified if it did. Traditionally, however, this syllogism is accepted as valid in this altered form:

P1: If each man had a definite set of rules of conduct by which he regulated his life he would be no better than a machine.

P2: However, most such rules that there are are ones that men themselves have made, and machines do not make rules beyond those they are built to follow.

C: Therefore, men are better than machines.

Jesus is savior[edit]

Another example can crop up among the careless of faith:

P1: If the Bible is correct, then we must accept Jesus as our personal savior.

P2: Jesus is my personal savior.

C: Therefore, the Bible is correct.

Here, the fallacy is that P1 and P2 may in fact be correct, but C is not a valid conclusion based on P1 and P2. It does not follow that the Bible must be correct because one person finds that Jesus is their savior, even if to a believer this seems like the case. More specifically, this is affirming the consequent, and is also a circular argument.

Belief in belief[edit]

A subtle but easy use of the fallacy is related slightly to belief in belief. It could be formed like this, which also contains an example of circular reasoning if you relabel the syllogism:

P(1): Religion gives great comfort to people and causes them to do good things.

P2/C1: These people are comforted and are good people.

C(2): Therefore God is real.

The non sequitur here is a failure to distinguish between what the act of believing can accomplish, and the (almost) completely unrelated question of the truth value of that belief. Someone could hold a belief in God and do good things (P1) but, because this is due to the belief itself, their good works and feelings of comfort (P2) would still be true whether God exists or not. Without external evidence to say otherwise, you cannot tell the difference between someone being comforted because God exists, or because they just believe God exists. (If you think that's not so, replace "God" above with Shiva or a god from another religion and see if that makes a compelling argument for that religion, or invert the language and see if that makes a compelling argument against any religion.) In short: the premises say nothing about the existence of God, only that some people believe in it.

However, it is simple to reword the syllogism so that it does have premises that say something about the existence of God:

P1: Several religions and spiritualities have the existence of some form of god(s) as an article of faith.

P2: People tend not to keep faith in un"real" things indefinitely.

C: Therefore, whatever form of God is believed is real for whoever believes in it.

The Future of God by Deepak Chopra and Everybody Is Wrong About God by James A. Lindsay (Ph.D.) are based on this rewording of the belief in belief syllogism to have premises that say something about the existence of God, though the latter only explicitly mentions the first kind of gods:

P1: There appear to be two kinds of gods: those who are simply projections of human desires or needs and those who are independent of human desires or needs.

P2: However, people stop needing to project any of their desires or needs which have been fulfilled.

C: Therefore only a God who is independent of human desires or needs can really be real.

And any premise about what the act of believing can accomplish has disappeared into thin air as well, but it was never really relevant to the demonstrandum anyway.

The ad hominem attack[edit]

P: You're a beautiful woman.

C: Therefore you're wrong.

The (ne quidem) non sequitur here is obvious: your status as a beautiful woman in no way affects the logical soundness or truth value of your arguments. One can be the most odious person in the history of humankind and yet make logically sound arguments based on demonstrably true premises.

External links[edit]

Perhaps you were looking for the Non Sequitur comic strip.
See the Wikipedia article on What's that got to do with the...?.

Notes[edit]

↑ Zippy the Pinhead^[1] is a core resource for rationalists with a sense of humour, who from time to time like to let their minds off the leash for a period of delightful unhingeditude. Arbitrary donuts optional.

References[edit]

↑ Zippy the Pinhead

[2] Zippy the Pinhead^[1] is a core resource for rationalists with a sense of humour, who from time to time like to let their minds off the leash for a period of delightful unhingeditude. Arbitrary donuts optional.

[1] Zippy the Pinhead

[note 1]

[1]

v - t - e Articles about logical fallacies
Informal fallacies:			Appeal to tradition • Appeal to novelty • Appeal to nature • Argument from morality • Argumentum ad martyrdom • Big words • Certum est quia impossibile est • Morton's fork • Friend argument • Exception that proves the rule • Extended analogy • Hindsight bias • Race card • Moralistic fallacy • Release the data • Gish Gallop • Terrorism-baiting • Uncertainty tactic • Greece-baiting • Ham Hightail • Red-baiting • Gore's Law • Nazi analogies • Mistaking the map for the territory • Red herring • Quidquid latine dictum sit, altum videtur • Presentism • Sunk cost • Two wrongs make a right • Flying carpet fallacy • My enemy's enemy • Appeal to ancient wisdom • Danth's Law • Argumentum ad lunam • Balance fallacy • Golden hammer • Loaded question • Escape to the future • Word magic • Spider-Man fallacy • Sanctioning the devil • Appeal to mystery • Informal fallacy • Common sense • Post-designation • Hyperbole • Relativist fallacy • Due diligence • Straw man • Good old days • Appeal to probability • Infinite regress • Circular reasoning • Media was wrong before • Is–ought problem • Ad iram • Just asking questions • Pink-baiting • Appeal to faith • Appeal to fear • Appeal to bias • Appeal to confidence • Appeal to consequences • Appeal to emotion • Appeal to flattery • Appeal to gravity • Appeal to hate • Argument from omniscience • Argument from silence • Argumentum ad baculum • Argumentum ad fastidium • Association fallacy • Broken window fallacy • Category mistake • Confounding factor • Counterfactual fallacy • Courtier's Reply • Damning with faint praise • Definitional fallacies • Equivocation • Fallacy of accent • Fallacy of accident • Fallacy of amphiboly • Gambler's fallacy • Imprecision fallacy • Moving the goalposts • Nirvana fallacy • Overprecision • Pathos gambit • Pragmatic fallacy • Quote mining • Argumentum ad sarcina inserta • Science doesn't know everything • Slothful induction • Spotlight fallacy • Style over substance • Toupee fallacy • Genuine but insignificant cause • Argument from incredulity • Appeal to age • Argumentum ad nauseam • Phantom distinction • Appeal to common sense • Argumentum ad hysteria • Omnipotence paradox • Argument from etymology • Appeal to trauma • Countless counterfeits fallacy •
	Ad hoc:		No True Scotsman • Moving the goalposts • Escape hatch • Handwave • Special pleading • Slothful induction • Nirvana fallacy • God of the gaps • PIDOOMA • Ad hoc • Tone argument •
	Arguments from ignorance:		Science doesn't know everything • Argument from incredulity • Argument from silence • Toupee fallacy • Appeal to censorship • Science was wrong before • Holmesian fallacy • Argument from omniscience • Willful ignorance • Argument from ignorance •
	Causation fallacies:		Post hoc, ergo propter hoc • Correlation does not imply causation • Wrong direction • Counterfactual fallacy • Regression fallacy • Gambler's fallacy • Denying the antecedent • Genuine but insignificant cause •
	Circular reasoning:		Infinite regress • Argument by assertion • Argumentum ad dictionarium • Appeal to faith • Circular reasoning • Self-refuting idea •
	Emotional appeals:		Appeal to fear • Appeal to emotion • Appeal to confidence • Deepity • Argumentum ad baculum • Appeal to shame • Appeal to flattery • Tone argument • Appeal to money • Argumentum ad fastidium • Appeal to gravity • Appeal to consequences • Loaded language • Style over substance • Appeal to pity • Appeal to hate • Pathos gambit • Shaming • Degenerate • Abomination •
	Fallacies of ambiguity:		Fallacy of accent • Equivocation • Fallacy of amphiboly • Quote mining • Fallacy of ambiguity • Moral equivalence • Scope fallacy • Suppressed correlative • Not as bad as • Etymology • Continuum fallacy • Wronger than wrong • Definitional fallacies • Code word • Phantom distinction •
Formal fallacies:			Confusion of the inverse • Denying the antecedent • Affirmative conclusion from a negative premise • Not even wrong • Chewbacca Defense • Affirming a disjunct • Illicit process • Four-term fallacy • Negative conclusion from affirmative premises • Fallacy fallacy • Substituting explanation for premise • Enthymeme • Syllogism • Formal fallacy • Existential assumption • Masked man fallacy • Self-refuting idea • Argument by gibberish • One single proof • Affirming the consequent • False dilemma • Conjunction fallacy •
Fallacious arguments:			Bumblebee argument • Fatwa envy • Gotcha argument • Hoyle's fallacy • Intuition pump • Logic and Creation • Not Circular Reasoning • Peanut butter argument • Great Beethoven fallacy • Fallacy of unique founding conditions • Evil is the absence of God • Argument from first cause • How do you know? Were you there? • Argument from design • Argument from beauty • Appeal to nature • Solferino fallacy • Religious scientists • Nothing to hide • Argument from fine tuning • Creep shaming • "I used to be an atheist" • Atheism as a religion • Argumentum ad populum • Argument from morality • Anti-environmentalism • Appeal to bias • Apophasis • Argumentum ad nauseam • Appeal to censorship • Argumentum ad sarcina inserta • Blaming the victim • Bait-and-switch • Danth's Law • Chewbacca Defense • Canard • DARVO • Demonization • Escape hatch • Friend argument • Everyone is racist • Gish Gallop • Greece-baiting • Gore's Law • Ham Hightail • Just asking questions • Leading question • Loaded language • Linking to authority • Loaded question • Lying by omission • Motte and bailey • Nazi analogies • Moving the goalposts • One single proof • Pink-baiting • One-way hash argument • Pathos gambit • Quote mining • Poisoning the well • Quidquid latine dictum sit, altum videtur • Race card • Red-baiting • Red herring • Release the data • Science was wrong before • Shill gambit • Straw man • Silent Majority • Uncertainty tactic • Style over substance • Terrorism-baiting • Weasel word • What's the harm (logical fallacy) • Whataboutism • Bullshit • Logical fallacy • Banana argument • Scapegoat • How come there are still monkeys? • Anti-racist is a code word for anti-white • Ontological argument • Omnipotence paradox • Presuppositionalism • Just a joke • Countless counterfeits fallacy •
Conditional fallacies:			Slippery slope • What's the harm (logical fallacy) • Special pleading • Conditional fallacy • On the spot fallacy • Appeal to the minority • Argumentum ad populum • Galileo gambit • Professor of nothing •
	Genetic fallacies:		Genetic fallacy •
		Appeals to authority:	Ipse dixit • Appeal to confidence • Argumentum ad populum • Argument from authority • Linking to authority • Silent Majority • Invincible authority • Appeal to celebrity • Ultracrepidarianism • Appeal to the minority • Galileo gambit • Appeal to identity • Weasel word • Professor of nothing • Euthyphro dilemma • Divine command theory •
		Ad hominem:	Ad iram • Argumentum ad cellarium • Bulverism • Poisoning the well • Blaming the victim • Tu quoque • Whataboutism • Nutpicking • Jonanism • Demonization • Shill gambit • Appeal to bias • Fallacy of opposition • Association fallacy • Damning with faint praise • Pathos gambit • Appeal to identity • Argumentum ad hominem • Nazi analogies • Not an argument • Nothing to hide • Scapegoat • 地下室论证 •
	Imprecision fallacies:		Apex fallacy • Overprecision • Cherry picking • Overgeneralization • Texas sharpshooter fallacy • False analogy • Appeal to fiction • Spotlight fallacy • Pragmatic fallacy • Selection bias • Anecdotal evidence • Category mistake • Nutpicking • Imprecision fallacy • Confounding factor • Fallacy of accident • Neyman's bias •
Valid logical methods:			Rapoport's Rules • Negative evidence • Reductio ad absurdum •
Fallacy collections:			SeekFind • Nizkor Project • Fallacy Files • Your Logical Fallacy Is • Logically Fallacious •

Non sequitur

Contents

Blatant examples[edit]

Men and machines[edit]

Jesus is savior[edit]

Belief in belief[edit]

The ad hominem attack[edit]

See also[edit]

Want to read this in another language?[edit]

External links[edit]

Notes[edit]

References[edit]

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