There are many logical fallacies, and over the next few weeks and months, I will occasionally focus on a fallacy. While fallacies are typically from the debating sphere and may seem out of place on a blog dedicated to writing, they do appear in writing as well. And not just in social media and blog comments either. They can appear in website and marketing copy, political speeches, opinion pieces, and so on.
Today’s fallacy is non sequitur.
What is the non sequitur fallacy?
A non sequitur argument is when the speaker’s conclusion doesn’t follow their premises.
You’ve probably actually heard an example of a non sequitur and not even realized that’s what it was. It often appears in jokes like, “If a 2×4 costs $6 and a 2×6 costs $8, how many pancakes does it take to cover a doghouse?”
Examples of the non sequitur fallacy
Here are some other examples of the non sequitur fallacy:
- John stood up for the ugly development that was planned for our neighbourhood. John should run for mayor.
- Sue loves swimming. She decided to fill up the main floor of her house with water.
- If the Bible is true, we must accept Jesus as our personal saviour. I accepted Jesus as my personal saviour, so the Bible is true.
- Global warming was caused by sunspots in the past and volcanoes. We still have sunspots and volcanoes, so it can’t be caused by humans.
- I bought this chair from your store last week, but it broke in just a few days. You carry nothing but crappy products.
In all the above examples, the speaker states a premise or two, but the conclusion never logically follows from those premises.
Just because John stood up to the developer doesn’t mean he will make a good mayor. A love of swimming doesn’t justify flooding one’s house. The Bible isn’t true just because someone did something it suggests you do, just like just because being Chinese makes you Asian doesn’t mean that being Asian also makes you Chinese. Just because certain phenomenon caused past global warming doesn’t mean other/additional causes might be causing it today. Just because a store sold one faulty product doesn’t mean the other hundreds or thousands of products they sell are faulty.
Using non sequitur is unfair to those you debate, and it’s intellectually lazy for you. Hopefully, these examples explain the importance of focusing on proposing logical arguments.
Which logical fallacy should I cover next? Let me know in the comments below.
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