Hasty Generalization

Michael J. Muniz

When Mexico sends its people, they’re not sending their best. They’re not sending you. They’re sending people that have lots of problems, and they’re bringing those problems to us.

Donald Trump

The fallacy of hasty generalization (HG) is one that can disrupt inductive reasoning. Before discussing the nature of HG, there needs to be a clear understanding of what defines a proper generalization.

According to Patrick Hurley (2008), a generalization is an “argument that proceeds from the knowledge of a selected sample to some claim about the whole group” (37). For example, after a teacher has graded 10 quizzes from a class of 25 and observes that each of them have gotten, say, question number 8 wrong with the same mistake, she can then argue that the remainder of the class will have probably gotten the same question wrong with the same or a similar mistake. Her generalization is justified because the sample is repre­sentative of the whole group. Given that she knows what was taught and how students learned the lesson that preceded the quiz, she induces that question number 8 must have been written in a way that was confusing for students. Additionally, she notes that 10 students in a class of 25 is a reason­able number from which to make such a generalization.

Regarding sampling, according to Michael Blastland and Andrew Dilnot (2008) in The Tiger That Isn’t, “samples have to be large enough to be plausibly representative of the rest of the population” (125). So, for the above example, 10 students are a plausible sample for a proper generalization about a group of 25.

Now, HG is committed when some aspect of the definition of the proper generalization is violated. In other words, the “hasty” aspect of this fallacy is triggered either (1) when there is a lack of knowledge of the selected sample or (2) when the selected sample is not representative of the whole group, or when both (1) and (2) are true.

To demonstrate the first trigger of the hasty part of HG, consider the example of a teacher who has a lack of knowledge of her students’ personal circumstances: “Johnny has been failing my quizzes this week. Therefore, Johnny is not capable of grasping my lesson.” The fallacy is committed in this case because the teacher failed to consider any possible factors inside and/or outside the classroom that may have contributed to Johnny’s failing the quizzes this week. Perhaps a close relative of Johnny might have passed away recently, causing him to not be focused, or perhaps Johnny is distracted in class by the pretty girl who sits next him.

The second trigger of the hasty part of HG is the most popular under­standing of the definition of this fallacy. It suggests that the sampling size is insufficient to represent the whole group. To demonstrate, suppose our teacher is grading a stack of 100 quizzes. By quiz 22, she observes that no student has gotten higher than a D on her quiz. Therefore, she believes that no student will receive at least a B on her quiz. But 22 quizzes are not a sufficient sample to generalize about a group of 100. Like this fictional teacher who does not utilize a large enough sample size, often in reality, we hold certain “truths” about some group or another based on either so-called scientific studies and/or polls that rely on small sample sizes.

To avoid committing this fallacy, the arguer should take into considera­tion the amount of justifiable knowledge she might have on a particular subject and whether the selected sample being used in the case is justifiably representative of the group in question. This means, the arguer should avoid stereotypes, typecasting, labels, and so on.

We see HG committed just about every day in politics and the media. Moreover, these instances of HG are employed intentionally to convey a specific point to the audience. In politics, HGs are used to emphasize the extremes of a particular viewpoint.

What can be simpler or more accurately stated? The Mexican Government is forcing their most unwanted people into the United States. They are, in many cases, criminals, drug dealers, rapists, etc.

Besides providing great sound bites and material for journalists and social critics to comment on, Mr. Trump’s remarks can also be quite entertaining. Concurrently, HG is used quite often by advertisers to promote a particular product. A common usage can be found in medical product commercials:

Nine out of 10 doctors recommend Advil to treat headaches. Therefore, it must be good.

Furthermore, these commercials are often not creating a stereotype for a product but are working with those already established by society. There is a popular “Guys Love Bacon” commercial by Taco Bell that works because of HG. In the commercial, one young lady has the newly developed bacon taco in her purse while her friend comments that it will not attract other men. Soon after, three men approach the young lady with the bacon taco in her purse. The commercial is suggesting that all men love bacon, and if a women smells like bacon, men will be attracted to her, which is simply not true.

References

Blastland, Michael, and A.W. Dilnot. 2008. The Tiger That Isn’t: Seeing through a World of Numbers. London: Profile.

Hurley, Patrick. 2008. A Concise Introduction to Logic, 10th edition. Belmont, CA: Wadsworth Cengage Learning.