3 Logical Fallacies to Avoid (and How to Tell When Someone Else is Committing Them)

Written by Mark Farnham

On September 21, 2018

Head in Hands[This post continues the short series on Logic and Apologetics posted previously.]

So far, we have looked at the basic structure of logic. Errors in the structure of logical arguments are called formal fallacies. For the sake of brevity, we don’t cover them in this book. Rather we move on to the most common mistakes in informal logic known as logical fallacies. These are flaws in reasoning that superficially seem to be sound, but upon examination are found to be false. The power of logical fallacies is that even after they have been shown to be flawed, they still retain their power to convince because they are often emotionally satisfying.

For example, many Christians believe the following statement to be true, even though it is a fallacy, because it gives them confidence: “Millions of people around the world and throughout history have found peace and hope in Jesus, therefore he must be the way to salvation.” While it is true that becoming a follower of Christ gives peace, that truth does not prove Christianity true. People feel a sense of peace through many means—other religions, no religion, meditation, addictive substances, catching a great wave, or a hike in the woods. This fallacy is called Appeal to Popularity, an argument based on what a large number of people think or believe. It reminds us that nothing is ever true just because it is popular or the majority position.

What follows is a short list of some popular logical fallacies that both believers and unbelievers tend to use in support of or opposition to the Christian faith. I will explain each one,[1]show examples of how both groups argue the fallacy, and then show what is wrong with both. This exercise should help us see that we need to present our reasons for what we believe in true and valid ways. Many of these fallacies have Latin names (post hoc, ad hominem, tu quoque), but for the sake of simplicity I have listed their common English names.

  1. Appeal to Authority—a claim is defended or advanced on the basis of those who believe it. While we may appeal to the arguments of experts in a particular field, just because recognized experts advocate or deny a position does not make it true or false. Nothing is ever true because of who said it, except God.

How Christians do this:

“Einstein believed in a higher being, and he was the smartest man in the 20thcentury, so you should too.”

“Billy Graham spoke to more people than any other evangelist in history, and everywhere he went people were converted, so that shows that the gospel is the truth for every person in the world.”

How unbelievers do this:

“93% of members of the National Academy of Science do not believe in God, so it is not reasonable to believe in God”—Richard Dawkins

“Bart Ehrman is a New York Times Bestselling author, a world-renowned professor at the University of North Carolina, and a graduate of Moody Bible Institute, and he says the manuscripts of the New Testament were corrupted, so it must be true.”

  1. Personal Attack—ignore the argument and criticize its author. Accusing the other person of being unreliable, ignorant, or lacking expertise says nothing about the validity of her argument, but it can have a strong emotional impact on listeners. This fallacy is a form of dishonesty because it distracts from the real issue at hand by focusing on something that has nothing to do with the argument, whether true or false.

How Christians do this:

 “Mormonism cannot be true. Look at the life and crimes of Joseph Smith!”

“How do you knowevolution is the way the world came about? Are youa scientist?

“Bill Nye only has an undergraduate degree in engineering, therefore he doesn’t know anything about biology or cosmology.”

How unbelievers do this:

“Ken Ham only has an undergraduate degree in applied science, so what could he know about advanced science?

“If Christianity was true then Christians would not be such hateful, bigoted, racist people.”

“The disciples were uneducated fisherman, so their ‘eyewitness testimony’ about Jesus’ resurrection was nothing more than hallucination and superstition.”

  1. False Cause—attributing a cause to an event or idea that is not the actual cause. Just because it rains every time you bring Sally with you on a picnic does not mean that Sally causes the rain. Just because your favorite baseball team wins whenever you are in your lucky chair wearing your lucky socks and eating pretzels does not mean that you are causing the wins with your actions.

How Christians do this:

“Attending public school makes teens more likely to walk away from their faith in college.”

“This nation started going downhill when prayer and Bible reading were taken out of schools.”

“The reason crime is on the rise is because people have stopped going to church.”

How unbelievers do this:

“As church attendance falls, violent crime declines; therefore, the faster we get rid of superstitious notions of God, the more peaceful our society will become.”

“Schools that teach children that they are good, and not sinners, have lower rates of failure.”

“Science flies you to the moon; religion flies you into buildings”—Physicist Victor Stenger

It is clear so far that believers and unbelievers alike can commit logical fallacies. In the next post we will look at 3 more logical fallacies that can arise in an apologetic discussion.

[1]Adapted from Stephen S Carey, The Uses and Abuses of Argument (Mayfield Publishing Company, 2000).

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