Fallacy of the Beard: Vague Doesn’t Necessarily Mean Invalid [#FallacyFridays]
Welcome to #FallacyFridays, the day for learning logical fallacies! Though these posts are posted every Friday, today is as good any to learn about the flaws in our logic that we might make. Today’s logical fallacy is the fallacy of the beard. 🧔🏾
(And no, the fallacy does not state that beards themselves can be logically fallacious. 😂)
Make sure to read all the way to the end so you can take the quiz to test your understanding of the fallacy. 🤓
But before we get into it, I want you to know about a tool that may help you understand this and other fallacies. I know that some people learn better by writing or typing. If that is you, download this FREE digital copy of “#FallacyFridays: The Workbook.” It was designed to follow alongside #FallacyFridays lessons in order for you to better understand logical fallacies.
The Origin of the Fallacy of the Beard
(aka the continuum fallacy, argument of the beard, line drawing fallacy)
Fallacies with funny names pretty much always have a backstory them. The fallacy of the beard is no exception. The first time the fallacy was used by its name was in 1930 in a book Straight and Crooked Thinking. In the book, Robert Thouless, psychologist and parapsychologist, writes the following:
One may throw doubt on the reality of a beard by a process beginning by asking whether a man with one hair on his chin has a beard. The answer is clearly ‘No.’ Then one may ask whether with two hairs on his chin a man has a beard. Again the answer must be ‘No.’ So again with ‘three, four,’ etc. At no point can our opponent say ‘Yes,’ for if he has answered ‘No’ for, let us say, 29 hairs and ‘Yes’ for thirty, it is easy to pour scorn on the suggestion that the difference between twenty-nine and thirty hairs is the difference between not having and having a beard. Yet by this process of adding one hair at a time, we can reach a number of hairs which would undoubtedly make up a beard. The trouble lies in the fact that the difference between a beard and no beard is like the difference between white and grey in the fact that one can pass by continuous steps from one to the other.
From Straight and Crooked Thinking by Robert Thouless (1930).
What is the Fallacy of the Beard?
Just as Thouless’ statement suggests, the fallacy of the beard shows how there might be a blurred line separating something on one end of the spectrum from another thing. In the case of Thouless’ statement, it was not having a beard vs. having a beard. The absurdity lies in claiming that 29 hairs on your chin means you don’t have a beard and saying 30 hairs means you do; 29 and 30 aren’t all that different from each other. In other words, the line where a non-beard becomes a beard is blurry.
The fallacy of the beard occurs when someone dismisses a claim by saying that there is no difference between itself and its opposite since a blurry line exists between them.
Using Thouless’ illustration, I would be committing the fallacy of the beard if I said that there is no difference between no beard and a beard because there is no definitive point that a beardless face becomes bearded. And because there is no firm distinction, the face is beardless no matter how many hairs I add.
The fallacy of the beard makes the mistake of claiming that blurred lines between things means that categories are useless. Click To TweetExamples of the Fallacy of the Beard
My teacher says that an 89.5% will count as an A in her class. I got an 85%. That’s only a difference of 4.5%. Such a little amount. This 89.5%+ range for A grades is useless. So while moving it to 85%+ could give me an A, it would be useless range too.
The legal voting age is 18 years old in the United States. But what really is the difference between the day before your 18th birthday and 18? 24 hours? How about 48 hours? 72? You can’t tell me the exact amount of hours that would make a difference, so having 18 as the legal voting age is not useful.
Janice told all of us to wear khaki pants for our photoshoot, but Ron’s pants look the most yellowish. I get that khaki is a spectrum of multiple shades, but there’s so little difference between Ron’s khaki pants and a faded yellow. You can’t tell the difference. Janice should have just let us wear whatever we wanted instead of using “khaki” as a legit category. Khaki and yellow is pretty much the same thing at this point.
In all of these examples, the categories A grade, age 18, and khaki are dismissed because, upon inspection, they exist on a continuum. And because of that lack of desired precision, they are rejected.
💡Key Point: Categories are immensely helpful in classifying things. Just because they might be vague because of how they exist on a spectrum does not automatically make them invalid.
Quiz Time
Now that you’ve learned what the fallacy of the beard is, here’s a quiz to test your understanding. Which one of the following answer choices contains the fallacy of the beard?
A. “Kayla took a bucket to the beach and scooped up the water in a medium-sized container. She brought it home and claims that she has the ocean in the bucket.”
B. “Black and white are obviously two very different colors. But I think dark gray should also go by the name “black lite.”
C. “This big bag of cotton balls is light. Since you can’t tell me exactly how many cotton balls it will take to get heavy, adding one more cotton after another won’t make a difference. So it will always be light.”
D. “The difference between novice and professional is often experience and practice.”
Enter your answer choice below! 👇🏾
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