Some Informal Argumentative Fallacies


Collated by Steve Vrooman, Feb. 2015


There are many more informal fallacies. There are also plenty of formal ones. The examples below are cited with hyperlinks. Most of those sources are good catalogs of the dozens, probably hundreds of fallacies. Some of the examples below are taken from websites with agendas, and those will be less helpful. For example, I have a few examples from both Christian and atheist wikis that seem to have it out for each other. These are organized by the fallacy family innovated by, except the first five, which have no family.







Black or White

A false dilemma that asserts an untrue “either-or” or forced choice.

“Well, it's time for a decision. Will you contribute $20 to our environmental fund, or are you on the side of environmental destruction?” IEP

I thought you were a good person, but you weren’t at church today.” Logically Fallacious

You ask how I can know that you're struggling financially?  It's simple: in a capitalist economy, you either win big or you lose big, and I know you're not one of the big winners.” TSU Philosophy



Appeal to Ignorance

Something is true because there is no evidence for it.

“If I were adopted, then I would know about it by now. 
I don't know that I'm adopted. 
Therefore, I wasn't adopted.” Fallacy Files

She hasn't said she doesn't like you, right? So she's probably interested. Call her up.” TSU Philosophy

Although we have proven that the moon is not made of spare ribs, we have not proven that its core cannot be filled with them; therefore, the moon’s core is filled with spare ribs.” Logically Fallacious


Begging the Question

A circular argument. The conclusion is part of a premise.

“Bill: "God must exist." 
Jill: "How do you know." 
Bill: "Because the Bible says so." 
Jill: "Why should I believe the Bible?" 
Bill: "Because the Bible was written by God." Nizkor Project

“Paranormal activity is real because I have experienced what can only be described as paranormal activity.” Logically Fallacious

People who deny the truth of Marxism are simply dancing to the tune of their capitalist masters, as Marx understood so well.” TSU Philosophy


Slippery Slope

A series of steps in a casual chain and the support/ probabilities for each is omitted in an argument that A basically causes Z.

“You know what happens when people take drugs! Pretty soon the caffeine won't be strong enough. Then you will take something stronger, maybe someone's diet pill. Then, something even stronger. Eventually, you will be doing cocaine. Then you will be a crack addict! So, don't drink that coffee.” IEP

"You can never give anyone a break. If you do, they'll walk all over you." Nizkor Project


If Texas adopts a personal income tax, I'm moving away. An income tax at the state level is just a first step to communism.” TSU Philosophy




A sweeping generalization of a fact or a rule, presented as if it has no exception.

“Birds normally can fly. 
Tweety the Penguin is a bird. 
Therefore, Tweety can fly.Fallacy Files

People should keep their promises, right? I loaned Dwayne my knife, and he said he'd return it. Now he is refusing to give it back, but I need it right now to slash up my neighbors who disrespected me.IEP

(1) Children should be seen and not heard.
(2) Little Wolfgang Amadeus is a child.
(3) Little Wolfgang Amadeus shouldn’t be heard.Logical Fallacies

Red Herrings

Red Herring

The premises of the argument are logically unrelated to the claim.

Cars kill more people than guns, and no one suggests we ban them.

Senator Clark: "Why are you not willing to support the antiabortion amendment? Don't you have any feelings at all for the unborn children whose lives are being indiscriminately blotted out?" Senator Rich: "I just don't understand why you people who get so worked up about lives being blotted out by abortion don't have the same feelings about the thousands of lives that are blotted out every year by the indiscriminate use of handguns. Is not the issue of the sanctity of human life involved in both issues? Why have you not supported us in our efforts at gun-control legislation?" TSU Philosophy


Jack: "Bob Dylan is the greatest performer of our time." Jill: "Well, Dylan is a fine writer, but as a performer, he stinks. I saw a concert of his once and we was singing unintelligibly and looked like he was falling asleep." Jack: "Well, Fleetwood Mac, one of your favorite groups, is not so great in concert either." TSU Philosophy


Straw Man

A person’s actual beliefs are misrepresented as something easier to attack and then attacked.

“Opponent: Because of the killing and suffering of Indians that followed Columbus's discovery of America, the City of Berkeley should declare that Columbus Day will no longer be observed in our city.

Speaker: This is ridiculous, fellow members of the city council. It's not true that everybody who ever came to America from another country somehow oppressed the Indians.” IEP

Pro-choice is absurd. How could anyone support killing an innocent human being?” TSU Philosophy

Ted: Biological evolution is both a theory and a fact.

Edwin: That is ridiculous!  How can you possibly be absolutely certain that we evolved from pond scum!” Logically Fallacious

Appeal to Misleading Authority (w/ Appeal to Celebrity & Appeal to Tradition)

Using an authority to affirm a conclusion when the authority is not expert enough, in the context, to assure the conclusion.

“The moon is covered with dust because the president of our neighborhood association said so.” IEP

“I'm not a doctor, but I play one on the hit series "Bimbos and Studmuffins in the OR." You can take it from me that when you need a fast acting, effective and safe pain killer there is nothing better than MorphiDope 2000. That is my considered medical opinion.” Nizkor Project


Sure I believe in God. People have believed in God for thousands of years so it seems clear that God must exist. After all, why else would the belief last so long?” Nizkor Project


Guilt by Association (w/ The Hitler Card)

An idea is wrong because a “bad” person agrees with it.

“Hitler was a vegetarian. 
Therefore, vegetarianism is wrong.” Fallacy Files        

Secretary of State Dean Acheson is too soft on communism, as you can see by his inviting so many fuzzy-headed liberals to his White House cocktail parties.” IEP

“For instance, in the 1960s some anti-communists attacked support for civil rights by pointing out that the Communist Party of the United States also supported the civil rights movement. It was then argued that supporting civil rights was tantamount to supporting communism.” Fallacy Files


Ad Hominem

An irrelevant attack on a person makes one of their arguments false.

What she says about Johannes Kepler's astronomy of the 1600s must be just so much garbage. Do you realize she's only fifteen years old?” IEP

Student: Hey, Professor Moore, we shouldn't have to read this book by Freud. Everyone knows he used cocaine.” TSU Philosophy


“Bill: "I believe that abortion is morally wrong." 
Dave: "Of course you would say that, you're a priest." 
Bill: "What about the arguments I gave to support my position?" 
Dave: "Those don't count. Like I said, you're a priest, so you have to say that abortion is wrong. Further, you are just a lackey to the Pope, so I can't believe what you say." Nizkor Project

Poisoning the Well

A preemptive ad hominem.

"Only an ignoramus would disagree with fluoridating water." Fallacy Files

Tim: Boss, you heard my side of the story why I think Bill should be fired and not me.  Now, I am sure Bill is going to come to you with some pathetic attempt to weasel out of this lie that he has created.” Logically Fallacious

"Before turning the floor over to my opponent, I ask you to remember that those who oppose my plans do not have the best wishes of the university at heart." Nizkor Project


Tu Quoque

An argument must be untrue since the author of the argument has acted inconsistently with the argument’s conclusions.

Look who's talking. You say I shouldn't become an alcoholic because it will hurt me and my family, yet you yourself are an alcoholic, so your argument can't be worth listening to.” IEP

Jill: "I think the gun control bill shouldn't be supported because it won't be effective and will waste money." 
Bill: "Well, just last month you supported the bill. So I guess you're wrong now." Nizkor Project


“Alice: Canada's health care policies are more effective than those of the United States.

Bob: If you like them so much, why don't you go live there?” RationalWiki

Appeal to Consequences

A proposition is true because belief in it leads to good things or it is untrue because that belief will lead to bad things.

Reducing greenhouse gas emissions would require policies we don't like, therefore anthropogenic greenhouse gasses don't have any effect on the climate.” RationalWiki

As long as I believe in Santa I will get presents.

“Belief in evolution and animal kinship leads normally to selfishness, aggressiveness, and fighting between groups, as well as animalistic attitudes and behaviour by individuals.” Fallacy Files

Appeal to Force/Fear

The conclusion should be accepted or I/we will do something bad to you.

“(1) If you don’t accept that the Sun orbits the Earth, rather than the other way around, then you’ll be excommunicated from the Church.
(2) The Sun orbits the Earth, rather than the other way around.” Logical Fallacies

"You know, Professor Smith, I really need to get an A in this class. I'd like to stop by during your office hours later to discuss my grade. I'll be in your building anyways, visiting my father. He's your dean, by the way. I'll see you later." Nizkor Project

Lucy makes a fist during this scene inducing her brother to do the Christmas play… “Lucy Van Pelt: "I'll give you five good reasons. One, two, three, four, FIVE!" Linus Van Pelt: "Those are good reasons. Christmas is not only getting too commercial, it's getting too dangerous." Hark


A popular idea is correct.

“Why should you feel guilty for seeking your own happiness when that's what everyone else is doing, too?” Fallacy Files

You should turn to channel 6. It's the most watched channel this year.” IEP

How could you not believe in virgin births?  Roughly two billion people believe in them, don’t you think you should reconsider your position?” Logically Fallacious

Emotional Appeal

Something is true because it makes us feel good or untrue because it doesn’t.

“Photographs of crippled or hungry children are shown in order to arouse one's desire to help them, with the charity trying to motivate you to write a check” Fallacy Files

There must be objective rights and wrongs in the universe.  If not, how can you possibly say that torturing babies for fun could ever be right?” Logically Fallacious

"I should receive an 'A' in this class. After all, if I don't get an 'A' I won't get the fellowship that I want." Nizkor Project


Wishful Thinking

Something is true because I want it to be.

“There's got to be an error here in the history book. It says Thomas Jefferson had slaves. I don't believe it. He was our best president, and a good president would never do such a thing. That would be awful.” IEP

I believe that when we die, we are all given new, young, perfect bodies, and we spend eternity with those whom we love.  I can’t imagine the point of life if it all just ends when we die!” Logically Fallacious

If special creation is true, then humans are made in the image of an all-powerful creator. I want to be have been made in the image of a creator. Therefore, special creation is true.” EvolutionWiki


 Weak Analogies

Weak Analogy

The two terms in the analogy are weakly or unrelated.

“Not believing in the literal resurrection of Jesus because the Bible has errors and contradictions, is like denying that the Titanic sank because eye-witnesses did not agree if the ship broke in half before or after it sank.” Logically Fallacious

“The book Investing for Dummies really helped me understand my finances better. The book Chess for Dummies was written by the same author, was published by the same press, and costs about the same amount. So, this chess book would probably help me understand my finances, too.IEP

During the Cold War, Congressman Charles Rose (Democrat, North Carolina) answered (in part) the arguments of those opposed to government-sponsored research to develop "remote-viewing" the ability to see a distant place telepathically by stating, "It seems to me that it would be a hell of a cheap radar system. This country wasn't afraid to look into the strange physics behind lasers and semiconductors, and I don't think we should be afraid to look into this.” TSU Philosophy

Unrepresentative Sample

A conclusion is drawn from an insufficiently representative sample.

“It has been concluded from a recent study involving more that 100,000 people in Florida that 43 percent of the American people now spend at least two hours a day in some form of recreational activity.” TSU Philosophy


“The Literary Digest, which began its famous straw poll with the 1916 presidential campaign, mailed out millions of mock ballots for each of its surveys. …

The results that poured in during the months leading up to the [1936 presidential] election showed a landslide victory for Republican Alf Landon.…Roosevelt was re-elected by an even greater margin than in 1932….The mailing lists the editors used were from directories of automobile owners and telephone subscribers… [which] were clearly weighted in favor of the Republicans in 1936. People prosperous enough to own cars have always tended to be somewhat more Republican than those who do not, and this was particularly true in [the] heart of the Depression.” Fallacy Files

Hasty Generalization

A conclusion is drawn from too small a sample of evidence.

My father smoked four packs of cigarettes a day since age fourteen and lived until age sixty-nine.  Therefore, smoking really can’t be that bad for you.Logically Fallacious

Californians are rude. Have you met Vrooman?


Children of faculty are brats. I baby-sit for one of my professors and his children are spoiled and demanding.” TSU Philosophy



Anecdotal Fallacy/

Misleading Vividness

A Hasty Generalization that relies on the availability heuristic (we generalize from vivid stories more readily).

"There's abundant proof that God exists and is still performing miracles today. Just last week I read about a girl who was dying of cancer. Her whole family went to church and prayed for her, and she was cured." SecularWeb

“[T]ravel insurance…is now purchased by half of American leisure travelers―a fivefold increase since 2001…” Fallacy Files

“Jane: "… I've been thinking about getting a Kiwi Fruit 2200. I read in that consumer magazine that they have been found to be very reliable in six independent industry studies." 
Bill: "I wouldn't get the Kiwi Fruit. A friend of mine bought one a month ago to finish his master's thesis. He was halfway through it when smoke started pouring out of the CPU. He didn't get his thesis done on time and he lost his financial aid. Now he's working over at the Gut Boy Burger Warehouse." Nizkor Project

 False Cause

Cum Hoc

Two things that happened at the same time must have a causal relationship.

“Gypsies live near our low-yield cornfields. So, gypsies are causing the low yield.” IEP

“Charging that welfare causes child poverty, [Gary Bauer] cites a study showing that "the highest increases in the rate of child poverty in recent years have occurred in those states which pay the highest welfare benefits. The lowest increases—or actual decreases—in child poverty have occurred in states which restrain the level of AFDC payments." Fallacy Files

“He sometimes behaves violently when I am around him. I don't know what it is that I am doing to make him become so violent.” Out of the Fog


Post Hoc

A thing that happens before another thing caused that.

“The only policy that effectively reduces public shootings is right-to-carry laws. Allowing citizens to carry concealed handguns reduces violent crime. In the 31 states that have passed right-to-carry laws since the mid-1980s, the number of multiple-victim public shootings and other violent crimes has dropped dramatically. Murders fell by 7.65%, rapes by 5.2%, aggravated assaults by 7%, and robberies by 3%.” Fallacy Files

…[E]vidence shows that even state and local handgun control laws work. For example, in 1974 Massachusetts passed the Bartley-Fox Law, which requires a special license to carry a handgun outside the home or business. The law is supported by a mandatory prison sentence. Studies by Glenn Pierce and William Bowers of Northeastern University documented that after the law was passed handgun homicides in Massachusetts fell 50% and the number of armed robberies dropped 35%. Fallacy Files

“I had been doing pretty poorly this season. Then my girlfriend gave me this neon laces for my spikes and I won my next three races. Those laces must be good luck...if I keep on wearing them I can't help but win!” Nizkor Project



Mistaking statistical regression to the man as a causal relationship.

“You are investigating the average heights of groups of people living in the United States. You sample some people living in Columbus, Ohio and determine their average height. You have the numerical figure for the mean height of people living in the U.S., and you notice that members of your sample from Columbus have an average height that differs from this mean. Your second sample of the same size is from people living in Dayton, Ohio. When you find that this group's average height is closer to the U.S. mean height [as it is very likely to be due to common statistical regression to the mean], you falsely conclude that there must be something causing people living in Dayton to be more like the average U.S. resident than people living in Columbus.” IEP

“I had a real bad headache, then saw my doctor.  Just by talking with him, my headache started to subside, and I was all better the next day.  It was well worth the $200 visit fee.” Logically Fallacious

“After surgery, my wife was not doing too well -- she was in a lot of pain.  I bought these magnetic wristbands that align with the body's natural vibrations to reduce the pain, and sure enough, a few days later the pain subsided!  Thank you magic wristbands!” Logically Fallacious

Texas Sharpshooter

Causal attributions are made about a cluster you analytically create. But the clustering effect make be chance or another cause.

“Psychic Sarah makes twenty-six predictions about what will happen next year. When one, but only one, of the predictions comes true, she says, "Aha! I can see into the future." IEP

“SuperCyberDate.con determined that Sally and Billy are a great match because they both like pizza, movies, junk food, Janet Jackson, and vote republican.” Logically Fallacious

“Abraham Lincoln and John F. Kennedy were both presidents of the United States, elected 100 years apart. Both were shot and killed by assassins who were known by three names with 15 letters, John Wilkes Booth and Lee Harvey Oswald, and neither killer would make it to trial. Spooky, huh? It gets better. Lincoln had a secretary named Kennedy, and Kennedy had a secretary named Lincoln. They were both killed on a Friday while sitting next to their wives, Lincoln in the Ford Theater, Kennedy in a Lincoln made by Ford. Both men were succeeded by a man named Johnson – Andrew for Lincoln and Lyndon for Kennedy. Andrew was born in 1808. Lyndon in 1908. What are the odds? You Are Not So Smart




A conclusion rests on grammatical ambiguity.

“One morning I shot an elephant in my pajamas. How he got into my pajamas I'll never know.” Fallacy Files

“Take this newspaper classified ad that appears under Furnished Apartments for Rent: “3 rooms, river view, private phone, bath, kitchen, utilities included” [It seems like the kitchen and bath are private as well, right? Ha!] About



An ambiguous word is used with two different meanings.

“The humanity of the patient's appendix is medically undeniable. 
Therefore, the appendix has a right to life and should not be surgically removed.” Fallacy Files

“All living beings come from other living beings.  Therefore, the first forms of life must have come from a living being.  That living being is God.” [note that “come from” in one case means procreation and in the other does not] Logically Fallacious

“Sure philosophy helps you argue better, but do we really need to encourage people to argue? There's enough hostility in this world.” TSU Philosophy


Scope Fallacy

The scope of a word is ambiguous and shifts.

“All that glitters is not gold. 
This rock glitters. 
Therefore, this rock is not gold.” Fallacy Files

“For every contingent being, there is a time when it does not exist. Therefore, there was a time when every contingent being did not exist. Because contingent beings cannot cause their own existence, their existence must have been caused by a necessary being - God.” [the 2nd sentence asserts the non-existence period was shared, but that does not follow. This is a change in the scope or reach of the idea in the 1st sentence.] About

“Necessarily, whatever happens, happens. Therefore, whatever happens, necessarily happens, so that whatever occurs could not have been otherwise.” SeekFind


The way you emphasize a word makes the conclusion seem more true.

“Jorge turned in his assignment on time todaaaaaaaaay.

Therefore, Jorge usually turns in his assignments late.” Philosophy Pages


“A member of Congress is asked by a reporter if she is in favor of the President's new missile defense system, and she responds, "I'm in favor of a missile defense system that effectively defends America." [”With an emphasis on the word "favor," her response is likely to favor the President's missile defense system. With an emphasis, instead, on the words "effectively defends," her remark is likely to be against the President's missile defense system”] IEP

“Suppose that two people are debating whether a rumour about the actions of a third person is true. The first says, “I can imagine him doing that; it’s possible.” The second replies, “Yes, it’s possible to imagine him doing that.” This looks like agreement.” [“If however, the second person stresses the word imagine, then this appearance vanishes; “Yes, it’s possible to imagine him doing that.” This now sounds like a pointed comment meaning that though it may just about be possible to imagine him doing that, there’s no way that he would actually do it.”] Logical Fallacies




Quantifier Shift

A “some” statement in a premise becomes an “all” in the conclusion.

“Everybody loves someone. 
Therefore, there is somebody whom everyone loves.” Fallacy Files

“Everything has a cause, so there's one cause of everything.” IEP

“Every person has some moral values (premise). Therefore, there are some moral values which every person shares with everyone else (conclusion).” About

Redefinition/ No True Scotsman

A term’s meaning is purposefully and creatively changed.

“And this is apparent, if we consider that every head of a family must look upon himself as obliged to act in three capacities—as a prophet, to instruct: as a priest, to pray for and with; as a king, to govern, direct, and provide for them.” Under Much Grace; example from Whitfield

“Scotsman A: You know, laddie, no Scotsman puts sugar in his porridge.

Scotsman B: Is that so? I seem to recall my cousin Angus (who is from Scotland) puts sugar in his porridge.

Scotsman A: Aye... but no true Scotsman puts sugar in his porridge.” Iron Chariots


“Our religion teaches people to be kind and peaceful and loving. Anyone who does evil acts certainly isnt acting in a loving manner, therefore they cant really be a true member of our religion, no matter what they say.” About