Nick McDonald
How Not to Argue Like an Idiot: The 15 Most Common Logical Fallacies
The protestant tradition is founded on “reason and the scriptures” – whether it’s Martin Luther standing before the Diet of Worms, C.S. Lewis apologetically defending the faith via radio waves, or Jonathon Edwards detailing the philosophical argument for the captivity of the soul – we are a community founded on the ability to reason. But I’ve used and heard plenty of bad reasoning from Christians. The following list is composed of some of the most common logical fallacies; I’ve chosen to limit it to only those I’ve actually heard in the last couple years.

Warning: I think logical fallacies have limited value; citing logic as the ultimate end-all of argumentation is itself a logical fallacy – it is a circular argument (I believe logic is authoritative because that’s logical) and it’s an appeal to authority (logic). That doesn’t mean, however, that its useless! Logic is a good tool, just not an authoritative tool.
Either way, whether you write or preach, communicator beware:
1. Ad Hominem – Attacking someone’s character rather than their argument. I was sitting with my friend a few weeks ago, debating the significance of a Greek word when he blurted out: “Well, they all translate it that way because theologians want people to go to hell!”
2. Straw Man. This essentially comes down to stating the argument of your opponent in a way they themselves wouldn’t have said it. I’ve heard countless sermons in hyper-conservative circles portraying non-Christians saying things I’ve never personally heard a non-Christian say.
3. False Analogy. In our age of creativity, this is probably the most common – how many times have I heard a debate “settled” because one person uses a beautiful analogy to illustrate their point? All analogies break down at some point; we need to know when and how in order to analyze them.
4. Slippery Slope. The argument that the extreme of a position must be true as well. I heard a Catholic radio DJ say that if we didn’t take the “body and blood” of Christ literally, we’d have to throw out his deity and the gospel itself as well. Or we might say, “If we allow homosexuals to marry, we must allow humans to marry dogs and cats and multiple partners, etc.” This is a different argument than the lesser to greater argument (by the very same principle, this also must be true) – sometimes it’s hard to tell the difference.
5. Confusion equals Cause. This argues that because we don’t understand something, God must be the solution. Because science can’t explain ______, God must be responsible.
6. Argument from Authority. I need to be careful here, because I believe ultimately, all of us argue from authority – whether it’s the authority of logic, experience, emotions, tradition, or the Bible. But still, we are to avoid arguments purely from authority; I must have a reason why I believe my authority is authoritative! Maybe a better way to say it is: “Argument from human authority”. After all, if our premise that God is omniscient and omnipotent is accurate, He doesn’t need to give us premises. That’s the whole point of the book of Job. We would do well to recognize as well that the reformation debate was over whether humans could claim Divine authority, with the assumption that Divine authority dictates truth.
7. Correlation equals Causation. Assuming that because two things happened simultaneously, one caused the other. For example, I’ve heard professionals say that listening to classical music increases intelligence, because studies done indicate there’s a correlation between the two. Later on, we found out this was bogus, considering all the other factors (for example, those who listen to classical music generally come from elitist cultures, generally indicating wealth, which means the family can afford better education).
8. Psychologist’s fallacy. Assuming that we are an unbiased audience. For example, citing our personal reading of scripture as the objective reading, and everyone else’s as “human opinion”.
9. False Dilemma. Giving two extremes as the only alternatives to a position, when really there are multiple positions: “Aka: If you don’t believe hell is eternal for everyone, you’re a universalist.” I fell into this one today when I cited my reasons I think guys should embrace singleness instead of waste their time dating. My friend corrected me by noting that his modified experience of dating allowed both he and his fiance to continue to take advantage of their singleness.
10. Moral Equivalence. Citing one complex moral event as being identical to another: “Abortion is just like the holocaust”
11. Meaningless Question: Assuming that all questions are logical, aka: “Can God create a rock so big he can’t lift it?” That’s like asking, “Can God create a lakjnsdfnj?” The question itself is illogical. God can do the impossible, but he cannot do anything illogical. I recently had someone ask me a meaningless question about my interpretation of a text, to which I replied, “What if I asked you the same question about a different verse of the Bible?” The question was the problem, not my befuddled inability to answer!
12. Argument from consequence. Because we don’t like the consequence, the argument must be false: “If we believe in the gift of prophecy today, then anyone can claim to speak God’s word.”
13. Red Herring. Continually changing the argument, rather than following it to its conclusion. AKA – when I asked a blogger why Jesus claimed to be God, he cited a whole host of other biblical passages about God being “one”.
14. Begging the Question. Assuming your premises, rather than explaining them. “Killing animals is wrong because it’s just plain gross!” or “Homosexuality is wrong because it’s disgusting!” These aren’t arguments – they’re begging the question.
15. Appeal to ignorance. “You can’t prove God doesn’t exist; therefore He does.” Once again, this is slightly different than saying: “scientific evidence doesn’t apply to metaphysical realities” – no one can prove scientifically for or against the existence of God, so both scientific sides of the argument are irrelevant.