Logical Fallacies and Causal Relationships
| Learning Objectives: - Identify logical fallacies relating to causal relationships.
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LESSON
A logical fallacyA mistake in reasoning; faulty thinking that weakens an argument or leads to an incorrect conclusion. is faulty reasoning used to support an ideaA thought, opinion, or impression., theoryIn science, a well tested and widely accepted explanation for a phenomenon. Theories incorporate facts, observations, experiments, laws, and careful reasoning. In more general usage, theory may merely mean an unproven idea, speculation, or guesswork., thesisAn overall argument, idea, or belief that a writer uses as the basis for a work., or hypothesisA preliminary explanation that needs further study before it can be accepted. A hypothesis is stronger than a guess but less supported than a theory.. When a careful reader identifies a logical fallacy, it may cause him or her to question the validity of the entire argumentA set of statements or reasons making a case for or against something., so it is important to identify logical fallacies in both your own and others' writing.
Think of logical fallacies as cracks in the foundation of a home. Some may be nearly naked to the invisible eye; others are large, gaping crevices. Either has the potential to eventually or suddenly cause your foundation to crumble and your house to fall. Logical fallacies in a textWords that make up a book, essay, article, poem, or speech. can work in the same fashion. Some may be challenging to spot; others may be quite obvious. Learning to identify and understand logical fallacies will help you better analyzeTo make a thoughtful and detailed study of something. the writing of others and know which arguments are strongest upon which to base your own reasoning.
In this lesson, you will be introduced to seven common logical fallacies.
- Slippery slope
The slippery slope fallacy is basically how it sounds. It is a premise that if "A" happens, then so will "B...C...D..." and so forth, through a series of small steps.
For example, if I do not get straight A's in high school, then I won't get into an Ivy League college, then I will not get a good job, and I will be stuck in a terrible job for the rest of my life.
- Post hoc fallacy or false cause
This fallacy implies that "A" caused "B" because "A" happened before "B."
For example, I chose not to wash my sports uniform. Our team won the game. We won the game because I did not wash my uniform. I will no longer wash my uniform before games so that we will continue to win.
- Genetic fallacy
This is the assumption that since "A" is associated with "B," "A" and "B" share the same good and bad traits.
For example, Hitler loved the work of the music composer Wagner. Since Hitler is associated with Wagner and Hitler was a terrible human being, Wagner must also be an equally terrible person.
- Cherry picking
Cherry picking is a fallacy that relies upon choosing only that dataFacts, numbers, or information. or evidenceFacts, statistics, or expert testimony that supports a claim. that will lead to your desired outcome rather than revealing the full picture.
This is not uncommon in the courtroom. Some attorneys may choose to ignore the evidence that goes against their cases, setting forth only the "facts" that support a verdict in favor of their clients.
- Fallacy of the single cause
This is the assumption that an event has only one cause.
For example, in the instance of a shutdown of a large corporation, we begin to ascribe one reason why it happened. We might say that the business mismanaged its finances and went bankrupt. However, there is usually more than a single cause for major events; in this case, it might also be that the company has engaged in illegal activities or the corporation was taken over by a global conglomerate in addition to the bankruptcy.
- Correlation proves causation
This is the logical fallacy that because "A" and "B" happen to occur at the same time, there is a causalDescribing or suggesting a cause. relationship.
For example, whenever I develop a rash, I put lotion on it and the rash goes away. The lotion must cause the rash to disappear. However, the rash may just go away eventually whether I put lotion on it or not.
- Reversing causal direction
This is the implication that "A" causes "B" without considering that "B" causes "A."
For example, each night when the streetlights turn on, the sun begins to set. The streetlights (A) must cause the sun to set (B). However, the streetlights obviously have no influence on the sun. The sun setting (B) is the reason the streetlights come on (A).
+ PRACTICAL APPLICATIONIt is just as important to be able to identify logical fallacies in your own writing as in that of others. When you present a faulty claim to your professor or boss, you undermine his or her faith in your judgment. Even if unsupported or incorrect reasoning is the only mistake you make, and it is minor, it is highly likely that your future work will be more closely considered for accuracy.
Understanding causal relationships is a necessary skill in the medical field. As a doctor assesses a patient's symptoms, he or she works to determine whether the symptoms are all caused by one problem or separate ailments. This information will lead to proper treatment of the patient's complaint; however, a misunderstanding of the symptoms' causes can lead the doctor to prescribe a treatment that actually makes the patient worse.
Below is a list of seven causal relationships that demonstrate a particular logical fallacy. For each causal relationship, notice which logical fallacy it exemplifies and why.
- Obesity in America is caused by the overwhelming prevalence of fast-food restaurants in our urban areas and highway rest stops.
This is an example of fallacy of a single cause. It assumesTo take for granted that something is true. that obesity in America has only one cause—fast-food restaurants—when in fact there are multiple causes, such as changes in school physical education programs, more time spent behind desks or in front of televisions, and the expense associated with more healthful food choices.
- If we continue to permit our children to play video games with fake guns, eventually most children will become immune to violence and more likely to become violent as adults. Therefore, we should not permit our children to play video games with fake weapons.
This is an example of a slippery slope fallacy. It sets forth the premise that A) if we allow children to play video games with fake guns, then B) they will become immune to violence, and C) are more likely to become criminals as adults. There is little evidence to support that children who play these video games become violent adults.
- I ordered a hot chocolate rather than my usual coffee before my job interview today. I did not get the job. I must always drink coffee before interviews if I hope to find employment.
This is an example of a post hoc fallacy or false cause. It implies that the failure to order coffee before a job interview caused the person to be turned down for the job because the failure to order coffee happened before the job interview. The selection of coffee or hot chocolate before a job interview is highly unlikely to have any impact on the outcome of that interview.
- All cats are antisocial and sneaky creatures. People who own cats are just as antisocial and sneaky.
This is an example of genetic fallacy. It assumes that A) since cats are associated with antisocial behavior and sneaky habits, B) cat owners must share the same bad traits. Simply because someone has a pet cat does not mean he or she shares the same attributes as the cat.
- Whenever I wear my brown leather boots, they get wet. My boots must absorb more moisture than other shoes.
This is an example of a correlation proves causation fallacy. It assumes that because A) every time the person wears the brown boots, B) they get wet, there is a causal relationship between the boots and wetness. There could be many explanations for this phenomenonHappenings or facts that can be observed. that are unrelated to the choice of footwear. For example, perhaps the person only wears those boots when it is snowy or rainy outside.
- People who are depressed suffer from worse acne, so depression must cause acne.
This is an example of a reversing causal direction fallacy. It sets forth the implication that A) depression causes B) acne without considering that B) terrible acne itself could cause A) depression.
- Working for a large corporation is much better than being employed by a small organization. The health benefits are better, there are more fun people to socialize with, and there is greater likelihood of being promoted from within.
This is an example of a cherry picking fallacy. It relies upon choosing only the data or evidence (all the fabulous perks of working for a large corporation) that will lead to your desired outcome (perhaps finding employment with a large corporation) rather than revealing the full picture (that there are plenty of perks to working for a smaller organization and that there are also negatives associated with working for a larger company).
Below is a list of seven causal relationships that demonstrate particular logical fallacies. Identify which logical fallacy each causal relationship exemplifies and why.
- Online dating is so impersonal. It has eroded the real-life, social nature of courtship and relationships. Online dating will lead to arranged marriages and a higher divorce rate.
Which logical fallacy is shown?
This is an example of a slippery slope fallacy.
Why?
It sets forth the premise that because A) online dating is so impersonal, B) it is responsible for the erosion of the real-life, social nature of courtship and relationships, and therefore C) it will lead to arranged marriages and a higher divorce rate.
- My nephew always cries after his mother leaves him alone in a room with me. My nephew doesn't like me.
Which logical fallacy is shown?
This is an example of a correlation proves causation fallacy.
Why?
It assumes that because A) the nephew cries whenever his mother leaves him alone with the person, B) the nephew doesn't like the person. There are many plausible explanations for this phenomenon. Perhaps the person always visits around lunchtime, and the nephew cries because he is hungry. Or maybe he has anxiety whenever his mother is out of sight.
- The newspaper industry is dying out because of the Internet.
Which logical fallacy is shown?
This is an example of a fallacy of a single cause.
Why?
It assumes the collapse of the newspaper industry has only one cause—the Internet. While this likely contributed to many newspapers closing down around the world, there are likely other causes, including cable news shows and an aging audience.
- Summer is better than winter because summer sports are more enjoyable than winter sports; plus, it's warm and sunny outside.
Which logical fallacy is shown?
This is an example of a cherry picking fallacy.
Why?
It relies upon choosing only the data or evidence (that summer sports are more fun and that it's sunny and warm) that will lead to a desired outcome (convincing someone that summer is better than winter) rather than revealing the full picture (there are things about the summer that many dislike—increased mosquito population, humidity, greater likelihood of sunburn, and so forth).
- There is no way that my cousin values the environment if he chooses to work for a company responsible for a large oil spill.
Which logical fallacy is shown?
This is an example of a genetic fallacy.
Why?
It assumes that A) the cousin is the same as B) a company responsible for a large oil spill. Simply because the cousin works for a company that acted irresponsibly in regards to the environment does not mean that he does not care for the environment.
- Children who are more outgoing and friendly prefer playing sports over joining math or chess clubs.
Which logical fallacy is shown?
This is an example of reversing causal direction fallacy.
Why?
It sets forth the implication that A) outgoing and friendly children B) would rather play sports than join a math or chess club. It does not consider the inverse relationship—that being part of a sports team encourages a more outgoing and friendly nature than math or chess clubs.
- My boyfriend always attends my cheerleading competitions. He failed to attend the last competition and we lost. If we are to continue winning competitions, my boyfriend must be in the audience.
Which logical fallacy is shown?
This is an example of a post hoc fallacy or false cause.
Why?
It implies that because the person's boyfriend did not attend the cheerleading competition, her team lost. Whether or not her boyfriend is in the audience, there are many factors that contribute to the winning or losing of such a competition. It is highly unlikely that there is any causal relationship between his failure to show up and the team's loss.
Why is it important to identify fallacies in others' writing?
Fallacies in others' writing may weaken the strength of their ideas. It is important to know how accurate and well developed others' writings are, particularly when I am using those sources to support my own arguments and reasoning.
Why is it important to identify fallacies in your own writing?
It is important to identify fallacies in my own writing for the same reason it is important to identify fallacies in others' writing. Fallacies can weaken the power of my arguments and make people question my reasoning. Fallacies can even pull apart my entire thesis, requiring me to rethink my whole essay. Additionally, fallacies in my own writing might make my teachers and bosses think less of my abilities as a student or employee.
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