Affirming a Disjunct: When “Either/Or” is Totally Flawed.
Welcome to #FallacyFridays! On Fridays, we explore logical fallacies, the flaws in our reasoning that you (and I) might be prone to making. But no matter when you see this, it’ll be beneficial to your intellectual growth. Today’s fallacy is called the affirming a disjunct fallacy. Make sure to read all the way to the end so you can take the quiz that tests 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.
What is the “Affirming a Disjunct” Fallacy?
You know those moments when someone assumes two things can’t coexist or cannot happen at the same time? You can’t help but be like, “Dude, those things aren’t mutually exclusive.” And they set a up scenario as if they are mutually exclusive and pick one option over the other? That’s pretty much the affirming a disjunct fallacy at work.
The affirming a disjunct fallacy occurs when, given an either/or scenario, you wrongly assume that if one statement or outcome is true, the other one cannot be true.
Since this a formal fallacy (the type of logical fallacy that is flawed due to the argument’s structure), it will be helpful to see how it works by looking at its form or structure. Let’s check it out below:
Either X or Y
It’s X
Therefore, it’s not Y
Example #1
Let’s look at the following example:
I recently lost my job. It’s either I stay struggling in life or I find a job. Since I found a job, I won’t struggle in life.
At first glance, this statement might seem true, but the latter half of the above statement might show the flaw a bit. After only a smidgen of digging, the issue is clear: having a job does not necessarily equal not struggling. The job may bring out issues that you won’t know about till you’re employed. You might struggle in life in other areas outside of your job. Having a job and struggling in life are not mutually exclusive.
Example #2
Doing jumping jacks is either a form of exercise or a form of aerobics. Since it is a form of aerobics, it is not exercise.
Now, this example is more obvious than the first. Aerobics is, by definition, a form of exercise. The “exercise vs. aerobics” dichotomy is wrong.
When you wrongly assume two things are mutually exclusive when they are not, you could be possibly making the affirming a disjunct fallacy. Click To TweetPro-Tip: There are tons of things people assume are mutually exclusive that aren’t. Write as many as you can to see how easy it can be to make the affirming a disjunct fallacy from that false dichotomy.
Quiz Time!
Now that you’ve learned what the affirming a disjunct fallacy is, here’s a quiz to test your understanding. Which one of the following answer choices contains the affirming a disjunct fallacy?
A. Kim: “Welcome to Gimby’s! Would you like a taco or a burger as your main food item?”
Kathy: “I would like a taco please.”
B. “They told me I could either get cheese or dairy with my meal, so I picked the cheese and did not get the dairy.”
C. “I want to be in a committed, happy relationship. Nothing less.”
D. “Would you rather go out Friday night? Or do you want to watch a movie in my house?”
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