Skip to main content
Humanities LibreTexts

2.4: Fallacies of Illicit Presumption

  • Page ID
  • This is a family of fallacies whose common characteristic is that they (often tacitly, implicitly) presume the truth of some claim that they’re not entitled to. They are arguments with a premise (again, often hidden) that is assumed to be true, but is actually a controversial claim, which at best requires support that’s not provided, which at worst is simply false. We will look at six fallacies under this heading.


    This fallacy is the reverse of the hasty generalization. That was a fallacious inference from insufficient particular premises to a general conclusion; accident is a fallacious inference from a general premise to a particular conclusion. What makes it fallacious is an illicit presumption: the general rule in the premise is assumed, incorrectly, not to have any exceptions; the particular conclusion fallaciously inferred is one of the exceptional cases.

    Here’s a simple example to help make that clear:

    Cutting people with knives is illegal.
    Surgeons cut people with knives.
    Therefore, surgeons should be arrested.

    One of the premises is the general claim that cutting people with knives is illegal. While this is true in almost all cases, there are exceptions—surgery among them. We pay surgeons lots of money to cut people with knives! It is therefore fallacious to conclude that surgeons should be arrested, since they are an exception to the general rule. The inference only goes through if we presume, incorrectly, that the rule is exceptionless.

    Another example. Suppose I volunteer at my first-grade daughter’s school; I go into her class one day to read a book aloud to the children. As I’m sitting down on the floor with the kiddies, criss-cross applesauce, as they say, I realize that I can’t comfortably sit that way because of the .44 Magnum revolver that I have tucked into my waistband. (That’s Dirty Harry’s gun, “the most powerful handgun in the world.”) So I remove the piece from my pants and set it down on the floor in front of me, among the circled-up children. The teacher screams and calls the office, the police are summoned, and I’m arrested. As they’re hauling me out of the room, I protest: “The Second Amendment to the Constitution guarantees my right to keep and bear arms! This state has a ‘concealed carry’ law, and I have a license to carry that gun! Let me go!”

    I’m committing the fallacy of Accident in this story. True, the Second Amendment guarantees the right to keep and bear arms; but that rule is not without exceptions. Similarly, concealed carry laws also have exceptions—among them being a prohibition on carrying weapons into elementary schools. My insistence on being released only makes sense if we presume, incorrectly, that the legal rules I’m citing are without exception.

    One more example from real life. After the financial crisis in 2008, the Federal Reserve—the central bank in the United States, whose task it is to create conditions leading to full employment and moderate inflation—found itself in a bind. The economy was in a free-fall, and unemployment rates were skyrocketing, but the usual tool it used to mitigate such problems—cutting the short- term federal funds rate (an interest rate banks charge each other for overnight loans)—was unavailable, because they had already cut the rate to zero (the lowest it could go). So they had to resort to unconventional monetary policies, among them something called “quantitative easing”. This involved the purchase, by the Federal Reserve, of financial assets like mortgage-backed securities and longer-term government debt (Treasury notes). (The hope was to push down interest rates on mortgages and government debt, encouraging people to buy houses and spend money instead of saving it—thus stimulating the economy.)

    Now, the nice thing about being the Federal Reserve is that when you want to buy something—in this case a bunch of financial assets—it’s really easy to pay for it: you have the power to create new money out of thin air! That’s what the Federal Reserve does; it controls the amount of money that exists. So if the Fed wants to buy, say, $10 million worth of securities from Bank of America, they just press a button and presto—$10 million dollars that didn’t exist a second ago comes into being as an asset of Bank of America. (It’s obviously a bit more complicated than that, but that’s the essence of it.)

    This quantitative easing policy was controversial. Many people worried that it would lead to runaway inflation. Generally speaking, the more money there is, the less each bit of it is worth. So creating more money makes things cost more—inflation. The Fed was creating money on a very large scale—on the order of a trillion dollars. Shouldn’t that lead to a huge amount of inflation?

    Economist Art Laffer thought so. In June of 2009, he wrote an op-ed in the Wall Street Journal warning that “[t]he unprecedented expansion of the money supply could make the '70s look benign.” (Art Laffer, “Get Ready for Inflation and Higher Interest Rates,” June 11, 2009, Wall Street Journal) (There was a lot of inflation in the ’70s.)

    Another famous economist, Paul Krugman, accused Laffer of committing the fallacy of accident. While it’s generally true that an increase in the supply of money leads to inflation, that rule is not without exceptions. He had described such exceptional circumstances in 1998 (But if current prices are not downwardly flexible, and the public expects price stability in the long run, the economy cannot get the expected inflation it needs; and in that situation the economy finds itself in a slump against which short-run monetary expansion, no matter how large, is ineffective.” From Paul Krugman, "It's baack: Japan's Slump and the Return of the Liquidity Trap," 1998, Brookings Papers on Economic Activity, 2), and pointed out that the economy of 2009 was in that condition (which economists call a “liquidity trap”): “Let meadd, for the 1.6 trillionth time, we are in a liquidity trap. And in such circumstances a rise in the monetary base does not lead to inflation.” (Paul Krugman, June 13, 2009, The New York Times)

    It turns out Krugman was correct. The expansion of the monetary supply did not lead to runaway inflation; as a matter of fact, inflation remained below the level that the Federal Reserve wanted, barely moving at all. Laffer had indeed committed the fallacy of accident.

    Begging the Question (Petitio Principii)

    First things first: ‘begging the question’ is not synonymous with ‘raising the question’; this is an extremely common usage, but it is wrong. You might hear a newscaster say, “Today Donald Trump’s private jet was spotted at the Indianapolis airport, which begs the question: ‘Will he choose Indiana Governor Mike Pence as running mate?’” This is a mistaken usage of ‘begs the question’; the newscaster should have said ‘raises the question’ instead.

    'Begging the question' is a translation of the Latin ‘petitio principii’, which refers to the practice of asking (begging, petitioning) your audience to grant you the truth of a claim (principle) as a premise in an argument—but it turns out that the claim you're asking for is either identical to, or presupposes the truth of, the very conclusion of the argument you're trying to make.

    In other words, when you beg the question, you're arguing in a circle: one of the reasons for believing the conclusion is the conclusion itself! It’s a Fallacy of Illicit Presumption where the proposition being presumed is the very proposition you’re trying to demonstrate; that’s clearly an illicit presumption. Here’s a stark example. If I'm trying to convince you that Donald Trump is a dangerous idiot (the conclusion of my argument is ‘Donald Trump is a dangerous idiot’), then I can't ask you to grant me the claim ‘Donald Trump is a dangerous idiot’. The premise can't be the same as the conclusion. Imagine a conversation:

    Me: “Because Donald Trump is a dangerous idiot.”
    You: “So you said. But why should I agree with you? Give me some reasons.”
    Me: “Here's a reason: Donald Trump is a dangerous idiot.”

    And round and round we go. Circular reasoning; begging the question.

    It's not always so blatant. Sometimes the premise is not identical to the conclusion, but merely presupposes its truth. Why should we believe that the Bible is true? Because it says so right there in the Bible that it's the infallible Word of God. This premise is not the same as the conclusion, but it can only support the conclusion if we take the Bible's word for its own truthfulness, i.e., if we assume that the Bible is true. But that was the very claim we were trying to prove!

    Sometimes the premise is just a re-wording of the conclusion. Consider this argument: “To allow every man unbounded freedom of speech must always be, on the whole, advantageous to the state; for it is highly conducive to the interests of the community that each individual should enjoy a liberty, perfectly unlimited, of expressing his sentiments.” (This is a classic example, from Richard Whately’s 1826 Elements of Logic.) Replacing synonyms with synonyms, this comes down to “Free speech is good for society because free speech is good for society.” Not a good argument. (Though it’s valid! P, therefore P is a valid form: if the premise is true, the conclusion must be; they’re the same.)

    Loaded Questions

    Loaded questions are questions the very asking of which presumes the truth of some claim. Asking these can be an effective debating technique, a way of sneaking a controversial claim into the discussion without having outright asserted it.

    The classic example of a loaded question is, “Have you stopped beating your wife?” Notice that this is a yes-or-no question, and no matter which answer one gives, one admits to beating his wife: if the answer is ‘no’, then the person continues to beat his wife; if the answer is ‘yes’, then he admits to beating his wife in the past. Either way, he’s a wife-beater. The question itself presumes the truth of this claim; that’s what makes it “loaded”.

    Strategic deployment of loaded yes-or-no questions can be an extremely effective debating technique. If you catch your opponent off-guard, they will struggle to respond to your question, since a simple ‘yes’ or ‘no’ commits them to the truth of the illicit presumption, which they want to deny. This makes them look evasive, shifty. And as they struggle to come up with a response, you can pounce on them: “It’s a simple question. Yes or no? Why won’t you answer the question?” It’s a great way to appear to be winning a debate, even if you don’t have a good argument. Imagine the following dialogue:

    Liberal TV Host: “Are you or are you not in favor of the president’s plan to force wealthy business owners to pay their fair share in taxes to protect the vulnerable and aid this nation’s underprivileged?”

    Conservative Guest: “Well, I don’t agree with the way you’ve laid out the question. As a matter of fact...”
    Host: “It’s a simple question. Should business owners pay their fair share; yes or no?”
    Guest: “You’re implying that the president’s plan would correct some injustice. But corporate taxes are already very...”
    Host: “Stop avoiding the question! It’s a simple yes or no!”

    Combine this with the sort of subconscious appeal to force discussed above—yelling, finger-pointing, etc.—and the host might come off looking like the winner of the debate, with his opponent appearing evasive, uncooperative, and inarticulate.

    Another use for loaded questions is the particularly sneaky political practice of “push polling”. In a normal opinion poll, you call people up to try to discover what their views are about the issues. In a push poll, you call people up pretending to be conducting a normal opinion poll, pretending only to be interested in discovering their views, but with a different intention entirely: you don’t want to know what their views are; you want to shape their views, to convince them of something. And you use loaded questions to do it.

    A famous example of this occurred during the Republican presidential primary in 2000. George W. Bush was the front-runner, but was facing a surprisingly strong challenge from the upstart John McCain. After McCain won the New Hampshire primary, he had a lot of momentum. The next state to vote was South Carolina; it was very important for the Bush campaign to defeat McCain there and reclaim the momentum. So they conducted a push poll designed to spread negative feelings about McCain—by implanting false beliefs among the voting public. “Pollsters” called voters and asked, “Would you be more or less likely to vote for John McCain for president if you knew he had fathered an illegitimate black child?” The aim, of course, is for voters to come to believe that McCain fathered an illegitimate black child. (Let’s face it, South Carolina has more racists than the average state. That’s just a demographic fact.) But he did no such thing. He and his wife adopted a daughter, Bridget, from Bangladesh.

    A final note on loaded questions: there’s a minimal sense in which every question is loaded. The social practice of asking questions is governed by implicit norms. One of these is that it’s only appropriate to ask a question when there’s some doubt about the answer. So every question carries with it the presumption that this norm is being adhered to, that it’s a reasonable question to ask, that the answer is not certain. One can exploit this fact, again to plant beliefs in listeners’ minds that they otherwise wouldn’t hold. In a particularly shameful bit of alarmist journalism, the cover of the July 1, 2016 issue of Newsweek asks the question, “Can ISIS Take Down Washington?” The cover is an alarming, eye-catching shade of yellow, and shows four missiles converging on the Capitol dome. The simple answer to the question, though, is ‘no, of course not’. There is no evidence that ISIS has the capacity to destroy the nation’s capital. But the very asking of the question presumes that it’s a reasonable thing to wonder about, that there might be a reason to think that the answer is ‘yes’. The goal is to scare readers (and sell magazines) by getting them to believe there might be such a threat.

    False Choice

    This fallacy occurs when someone tries to convince you of something by presenting it as one of limited number of options and the best choice among those options. The illicit presumption is that the options are limited in the way presented; in fact, there are additional options that are not offered. The choice you’re asked to make is a false choice, since not all the possibilities have been presented.

    Most frequently, the number of options offered is two. In this case, you’re being presented with a false dilemma. I manipulate my kids with false choices all the time. My younger daughter, for example, loves cucumbers; they’re her favorite vegetable by far. We have a rule at dinner: you’ve got to choose a vegetable to eat. Given her ’druthers, she’d choose cucumber every night. Carrots are pretty good, too; they’re the second choice. But I need her to have some more variety, so I’ll sometimes lie and tell her we’re out of cucumbers and carrots, and that we only have two options: broccoli or green beans, for example. That’s a false choice; I’ve deliberately left out other options. I give her the false choice as a way of manipulating her into choosing green beans, because I know she dislikes broccoli.

    Politicians often treat us like children, presenting their preferred policies as the only acceptable choice among an artificially restricted set of options. We might be told, for example, that we need to raise the retirement age or cut Social Security benefits across the board; the budget can’t keep up with the rising number of retirees. Well, nobody wants to cut benefits, so we have to raise the retirement age. Bummer. But it’s a false choice. There are any number of alternative options for funding an increasing number of retirees: tax increases, re-allocation of other funds, means-testing for benefits, etc.

    Liberals are often ambivalent about free trade agreements. On the one hand, access to American markets can help raise the living standards of people from poor countries around the world; on the other hand, such agreements can lead to fewer jobs for American workers in certain sectors of the economy (e.g., manufacturing). So what to do? Support such agreements or not? Seems like an impossible choice: harm the global poor or harm American workers. But it may be a false choice, as this economist argues:

    But trade rules that are more sensitive to social and equity concerns in the advanced countries are not inherently in conflict with economic growth in poor countries. Globalization’s cheerleaders do considerable damage to their cause by framing the issue as a stark choice between existing trade arrangements and the persistence of global poverty. And progressives needlessly force themselves into an undesirable tradeoff... Progressives should not buy into a false and counter-productive narrative that sets the interests of the global poor against the interests of rich countries’ lower and middle classes. With sufficient institutional imagination, the global trade regime can be reformed to the benefit of both. (Dani Rodrik, “A Progressive Logic of Trade,” Project Syndicate, 4/13/2016)

    When you think about it, almost every election in America is a False Choice. With the dominance of the two major political parties, we’re normally presented with a stark, sometimes unpalatable, choice between only two options: the Democrat or the Republican. But of course if enough people decided to vote for a third-party candidate, that person could win. Such candidates do exist. But it’s perceived as wasting a vote when you choose someone like that. This fact was memorably highlighted on The Simpsons back in the fall of 1996, before the presidential election between Bill Clinton and Bob Dole. In the episode, the diabolical, scheming aliens Kang and Kodos (the green guys with the tentacles and giant heads who drool constantly) contrive to abduct the two major-party candidates and perform a “bio-duplication” procedure that allows Kang and Kodos to appear as Dole and Clinton, respectively. The disguised aliens hit the campaign trail and give speeches, making bizarre campaign promises. (Kodos: “I am Clin-ton. As overlord, all will kneel trembling before me and obey my brutal command. End communication.”) When Homer reveals the subterfuge to a horrified crowd, Kodos taunts the voters: “It’s true; we are aliens. But what are you going to do about it? It’s a two-party system. You have to vote for one of us.” When a guy in the crowd declares his intention to vote for a third-party candidate, Kang responds, “Go ahead, throw your vote away!” Then Kang and Kodos laugh maniacally. Later, as Marge and Homer—chained together and wearing neck-collars—are being whipped by an alien slave-driver, Marge complains and Homer quips, “Don’t blame me; I voted for Kodos.”


    The fallacy of Composition rests on an illicit presumption about the relationship between a whole thing and the parts that make it up. This is an intuitive distinction, between whole and parts: for example, a person can be considered as a whole individual thing; it is made up of lots of parts—hands, feet, brain, lungs, etc., etc. We commit the fallacy of Composition when we mistakenly assume that any property that all of the parts share is also a property of the whole. Schematically, it looks like this:

    All of the parts of X have property P.
    Any property shared by all of the parts of a thing is also a property of the whole.
    Therefore, X has the property P.

    The second premise is the illicit presumption that makes this argument go through. It is illicit because it is simply false: sometimes all the parts of something have a property in common, but the whole does not have that property.

    Consider the 1980 U.S. Men’s Hockey Team. They won the gold medal at the Olympics that year, beating the unstoppable-seeming Russian team in the semifinals. (That game is often referred to as “The Miracle on Ice” after announcer Al Michaels’ memorable call as the seconds ticked off at the end: “Do you believe in miracles? Yes!”) Famously, the U.S. team that year was a rag-tag collection of no-name college guys; the average age on the team was 21, making them the youngest team ever to compete for the U.S. in the Olympics. The Russian team, on the other hand, was packed with seasoned hockey veterans with world-class talent.

    In this example, the team is the whole, and the individual players on the team are the parts. It’s safe to say that one of the properties that all of the parts shared was mediocrity—at least, by the standards of international competition at the time. They were all good hockey players, of course—Division I college athletes—but compared to the Hall of Famers the Russians had, they were mediocre at best. So, all of the parts have the property of being mediocre. But it would be a mistake to conclude that the whole made up of those parts—the 1980 U.S. Men’s Hockey Team—also had that property. The team was not mediocre; they defeated the Russians and won the gold medal! They were a classic example of the whole being greater than the sum of its parts.


    The fallacy of Division is the exact reverse of the fallacy of Composition. It’s an inference from the fact that a whole has some property to a conclusion that a part of that whole has the same property, based on the illicit presumption that wholes and parts must have the same properties. Schematically:

    X has the property P.
    Any property of a whole thing is shared by all of its parts.
    Therefore, x, which is a part of X, has property P.

    The second premise is the illicit presumption. It is false, because sometimes parts of things don’t have the same properties as the whole. George Clooney is handsome; does it follow that his large intestine is also handsome? Of course not. Toy Story 3 is a funny movie. Remember when Mr. Potato Head had to use a tortilla for his body? Or when Buzz gets flipped into Spanish mode and does the flamenco dance with Jessie? Hilarious. But not all of the parts of the movie are funny. When it looks like all the toys are about to be incinerated at the dump? When Andy finally drives off to college? Not funny at all! (I admit it: I teared up a bit; I’m not ashamed.)