Logic, Fallacies and Character

What you'll learn

Identify twelve common logical fallacies in apologetics conversations, including your own
Distinguish vicious circular reasoning from transcendental reasoning
Apply 1 Peter 3:15-16, 2 Timothy 2:24-26 and Colossians 4:5-6 to hostile and online situations

Why logic belongs to God

Logic is not a neutral human invention that stands above God. The laws of logic, such as the law of non-contradiction (something cannot be both true and false in the same sense at the same time), reflect the consistent character of God, who cannot lie or deny himself (Titus 1:2; 2 Tim 2:13). That is why Christians, of all people, should reason carefully.

A fallacy is an error in reasoning that makes an argument look stronger than it is. Learning fallacies helps you spot weak objections, but it also humbles you, because you will catch yourself committing them. Use them as tools for clarity, not as insults. Saying 'That's a straw man!' is less helpful than 'I don't think that's what Christians believe; let me explain.'

Why does the lesson say logic 'belongs to God' rather than being a neutral human invention?Show answer

The laws of logic, such as the law of non-contradiction, reflect the consistent character of God, who cannot lie or deny himself (Titus 1:2; 2 Tim 2:13). They are not a human invention that stands above God. That is why Christians, of all people, should reason carefully.

Reflects God's consistency
Non-contradiction
God cannot lie (Titus 1:2)
Christians should reason carefully

How should Christians use their knowledge of fallacies, according to the lesson?Show answer

A fallacy is an error in reasoning that makes an argument look stronger than it is. Learning them helps you spot weak objections, but it should also humble you because you will catch yourself committing them. Use them as tools for clarity, not insults: say 'I don't think that's what Christians believe; let me explain' rather than 'That's a straw man!'

Error that looks strong
Humbles us too
Clarity, not insults
Explain rather than label

Twelve common fallacies

Here are twelve you will meet often, each with an apologetics example.

Ad hominem (attacking the person, not the argument): 'You only believe that because you're a religious nut.' Christians do this too: 'Of course he denies God; he just wants to sin.'
Tu quoque ('you too'): 'Christians can't talk about morality; look at the Crusades.' Hypocrisy, if real, does not make a claim false.
Straw man (attacking a distorted version): 'Christians believe in a sky daddy who hates fun.' Or a Christian saying 'Evolutionists believe a monkey gave birth to a human.'
Genetic fallacy (judging a belief by its origin): 'You're only a Christian because you were raised in a Christian home.' Where a belief came from does not decide whether it is true.
Special pleading (exempting your case from a rule without justification): 'Everything needs a cause, except the universe.' Note: Christians are not special pleading when they say whatever begins to exist has a cause, since God did not begin (this is the Kalam cosmological argument; Foundations of Defence, Lesson 3).
Equivocation (shifting a word's meaning mid-argument): 'Evolution is a fact because things change; therefore unguided macroevolution explains everything.' Or 'faith' used first as trust and later as 'belief without evidence'.
Begging the question (assuming what you are trying to prove): 'Miracles cannot happen, so the resurrection didn't happen.' The conclusion is hidden in the premise.
Red herring (changing the subject): asked about the evidence for the empty tomb, someone switches to 'What about the genocide in the Old Testament?'
False dilemma (only two options when there are more): 'Either science or God.' Many great scientists, such as Newton, Faraday and Maxwell, believed in both.
Illegitimate appeal to authority: 'My physics professor says the Bible is full of myths.' A physicist is not an authority on ancient history.
Chronological snobbery (C. S. Lewis's term): 'That's an ancient book; we know better now.' Age alone does not make a claim true or false.
Appeal to popularity (ad populum): 'Most people don't believe in hell anymore.' Truth is not determined by vote.

What is the difference between an ad hominem and a genetic fallacy? Give an example of each.Show answer

An ad hominem attacks the person instead of the argument, such as 'You only believe that because you're a religious nut' (and Christians can do this too). A genetic fallacy judges a belief by where it came from, such as 'You're only a Christian because you were raised in a Christian home'. In both cases the claim's truth is left untouched.

Ad hominem attacks person
Genetic judges by origin
Correct examples
Truth not addressed

Someone says, 'Either science or God, you can't have both.' Which fallacy is this, and how would you answer?Show answer

This is a false dilemma: it offers only two options when there are more. You could point out that many great scientists, such as Newton, Faraday and Maxwell, believed in both science and God. So the two are not exclusive alternatives.

False dilemma
More than two options
Newton, Faraday, Maxwell

Begging the question versus transcendental reasoning

Critics often say presuppositional apologetics begs the question: 'You assume the Bible is true to prove the Bible is true.' The distinction matters.

Vicious circularity is assuming a narrow conclusion in a premise: 'The Bible is true because the Bible says so, and that's the end of it.' That persuades no one and proves nothing.

Transcendental reasoning asks what must be true for something else to be possible at all. Bahnsen argued (as you saw in Foundations of Defence, Lesson 2) that the Christian worldview is the necessary precondition for logic, science and morality, and that every alternative worldview, examined on its own terms, cannot account for them. This is sometimes called arguing from 'the impossibility of the contrary'. Every worldview has an ultimate authority that cannot be proven by something higher; even the rationalist must use reason to defend reason. The question is which ultimate authority makes sense of the world.

Classical apologists such as Craig would argue that we should begin with shared premises and evidence rather than worldview-level arguments, and the two schools debate this. For practical purposes, you can learn from both: avoid narrow circular arguments, and be ready to show that the unbeliever's own reasoning depends on a world only God explains.

What is the difference between vicious circularity and transcendental reasoning?Show answer

Vicious circularity assumes a narrow conclusion in a premise, such as 'The Bible is true because the Bible says so, and that's the end of it', which proves nothing. Transcendental reasoning asks what must be true for something else to be possible, arguing that the Christian worldview is the necessary precondition for logic, science and morality (the impossibility of the contrary). Every worldview has an ultimate authority that cannot be proven by something higher, so the question is which one makes sense of the world.

Vicious: conclusion in premise
Transcendental: preconditions
Impossibility of the contrary
Every worldview has an ultimate authority

Gentleness and respect

First Peter 3:15-16 is the classic apologetics text. Notice its order: first 'in your hearts honour Christ the Lord as holy', then 'always being prepared to make a defence', then 'with gentleness and respect, having a good conscience'. Our inner life with Christ comes before our arguments, and our manner matters as much as our content, so that those who slander us are put to shame.

Second Timothy 2:24-26 says the Lord's servant must not be quarrelsome but kind to everyone, able to teach, patiently enduring evil, correcting opponents with gentleness. Why? Because 'God may perhaps grant them repentance'. They are not enemies to be defeated but captives to be freed.

Colossians 4:5-6 asks us to let our speech always be gracious, seasoned with salt. Salt preserves and adds flavour; it also stings a little. Grace without truth is flattery; truth without grace is cruelty.

What does the order of 1 Peter 3:15-16 teach about how we do apologetics?Show answer

First we honour Christ as holy in our hearts, then we are prepared to make a defence, and we do it with gentleness and respect and a good conscience. Our inner life with Christ comes before our arguments. Our manner matters as much as our content, so that those who slander us are put to shame.

Heart first
Then prepared defence
Gentleness and respect
Manner as important as content

Handling hostility and online pile-ons

Online conversations bring special temptations: anonymity, speed and an audience that rewards mockery. If you post apologetics content, you will at some point face a pile-on, where dozens of people attack at once.

Do not respond while angry. Wait, pray and reread before posting (Jas 1:19-20).
Answer the best objection, not the loudest. You do not have to reply to everyone.
Move promising conversations to a private message or a video call, where tone is clearer.
Never return insult for insult (1 Pet 3:9). A soft answer turns away wrath (Prov 15:1).
Admit mistakes publicly and quickly. Correcting yourself builds trust and honours Christ.
Protect your own soul: limit time online, stay rooted in your local church and do not let your sense of worth depend on winning comment threads.

Choose three of the lesson's guidelines for online pile-ons and explain why each is wise.Show answer

Do not respond while angry, but wait, pray and reread (Jas 1:19-20), because anger produces careless words. Answer the best objection, not the loudest, since you do not have to reply to everyone. Never return insult for insult (1 Pet 3:9), and admit mistakes publicly and quickly, because correcting yourself builds trust and honours Christ.

Don't post angry
Answer the best objection
No insult for insult
Admit mistakes; protect your soul

In their own words

“The fallacy-hunter: labelling every argument a fallacy ('That's an appeal to authority!') without engaging its substance.” (Common online tactic; ask them to show which premise fails)

“The pile-on: many accounts attacking at once, often with mockery and memes, to overwhelm and discredit.” (Common social media dynamic)

“The circularity charge: 'You use the Bible to prove the Bible, so your whole worldview is circular.'” (Standard objection to presuppositional apologetics)

“The tone police: shifting from your argument to complaints about your manner, sometimes fairly and sometimes as a deflection.” (Common; take fair criticism seriously, then return to the issue)

Key texts

1 Peter 3:15-16: Honour Christ in your heart, be ready with a defence, and give it with gentleness and respect. The foundational apologetics text.
2 Timothy 2:24-26: Kindness and patience serve the hope that God will grant repentance; opponents are captives, not enemies.
Colossians 4:5-6: Gracious, salty speech that knows how to answer each person.
Proverbs 15:1: A soft answer turns away wrath. Essential in hostile and online settings.
James 1:19-20: Quick to hear, slow to speak, slow to anger, because human anger does not produce God's righteousness.
Titus 1:2; 2 Timothy 2:13: God cannot lie or deny himself. Logic reflects his consistent character.

Objections and answers

Try answering each one yourself before you open the response.

“Christians are always guilty of special pleading: everything needs a cause, except God.”Show a response

That would be special pleading if Christians claimed everything needs a cause. But the cosmological argument says that whatever begins to exist has a cause. The universe began to exist, as standard big bang cosmology indicates, so it needs a cause. God, by definition, is eternal and did not begin to exist, so he does not need one. That is a principled distinction, not an exception made up for convenience. You might ask, why couldn't the universe be eternal? That's a fair question we can discuss with the evidence. But notice that the atheist who says 'the universe just is' is also accepting something uncaused. The question is which uncaused reality best explains everything else.

“You tell me to be gentle, but Jesus called the Pharisees 'whitewashed tombs' and a 'brood of vipers'.”Show a response

Jesus did speak sharply, and we should notice to whom. His strongest words were directed at religious leaders who claimed to speak for God while burdening others (Matt 23). With sinners, outsiders and the confused, he was patient and kind, like with the Samaritan woman (John 4). Also, Jesus could see hearts perfectly; we can't. Paul, who also rebuked false teachers, told Timothy to correct opponents with gentleness (2 Tim 2:25). So there is a place for sharp words, but it is rare, usually aimed at false teachers rather than seekers, and never driven by pride or anger. Most of us need to grow in gentleness, not in harshness.

“Your God is the ultimate ad hominem. You say people reject God because they're sinful, so you never have to engage their arguments.”Show a response

That's a fair warning, and some Christians do use Romans 1 that way. It would be an ad hominem if I said, 'You only reject God because you love sin, so your argument is wrong,' and stopped there. That would be bad reasoning and unkind. Romans 1 does teach that we all suppress the truth about God, and I include myself before I became a Christian. But that is a theological diagnosis, not a substitute for engaging what you say. So please give me your best argument, and I will engage it on its merits. If I can't answer it, I'll say so. I think the arguments for Christianity are strong, and I'm happy to show them rather than just assert them.

“Logic is just a human convention, like grammar. It doesn't point to God; we made it up because it's useful.”Show a response

That's an interesting view, and I'd like to understand it. But notice what happens when we test it. If the law of non-contradiction were only a convention, then the statement 'logic is just a convention' could be both true and false at the same time, and your argument would lose its force. In fact, to argue for your view you have to rely on logic being binding on both of us, not just useful. Grammar varies from language to language, but non-contradiction holds everywhere and for everyone. Christians think that is because logic reflects the consistent character of God, who cannot lie or deny himself (Titus 1:2; 2 Tim 2:13). The question is which worldview best explains why such universal laws exist at all.

“You talk about gentleness, but online Christians are some of the nastiest people around. Why should I listen to any of you?”Show a response

I'm sorry, and I mean that. Some Christians online are harsh, and sometimes I've been more interested in winning than in loving people. Scripture actually condemns that: the Lord's servant must not be quarrelsome but kind to everyone, correcting opponents with gentleness (2 Tim 2:24-25), and we are told never to repay insult with insult (1 Pet 3:9). So when Christians behave badly, they are failing by Jesus' own standard, not following it. At the same time, how Christians behave doesn't decide whether Christianity is true; that would be a tu quoque. The question of whether Jesus rose from the dead stands or falls on the evidence. I'd love to talk about that with you, and I'll try to do it kindly.

Written task

Find (or write) a short online exchange of about 150 words in which a sceptic criticises Christianity and a Christian responds badly. Identify at least four fallacies committed across both sides, explain each in one or two sentences, and then rewrite the Christian's reply (150-250 words) in a way that is logically sound and reflects 1 Peter 3:15-16.

Hand this in to Mr Scott. He will look for:

Correctly identifies and explains at least four fallacies
Identifies at least one fallacy committed by the Christian, showing self-awareness
Rewritten reply engages the sceptic's real argument rather than a distortion
Rewritten reply shows gentleness and respect and avoids sarcasm
Points back to Christ or the gospel naturally