The classic text which motivates Christian apologetics (the defense of the faith) is 1 Peter 3:15,

But sanctify the Lord God in your hearts: and be ready always to give an answer to every man that asketh you a reason of the hope that is in you with meekness and fear.

This text gives the reason why every Christian should be prepared to defend the faith: because God says so. Naturally, God has a reason why He would say so as well, and that reason is the salvation of sinners and the ultimate glory of His Name. Therefore we are to be ready always. The answer which we must be prepared to give is a well-reasoned one, as the original Greek "apologia" (from where we get the word "apologetics") indicates. It would thus be reprehensible if Christians were to be ready to defend their faith in a sloppy way, giving no heed to rules of reasoning.

Christians need not fear atheists and agnostics (such as Charles Templeton) as long as they know their Bibles and some basic rules of logic or reasoning. What I would like to do, is to alert you to some common mistakes people make when arguing about the Christian faith. In doing this, we should begin by reaffirming that our faith does not rest upon logic or reason. Christian faith is reasonable, but it is not rationalistic. It is necessary to make it clear that faith is produced by the Holy Spirit through the preaching of the Scriptures. Our faith is built upon the solid bedrock of the promises found in God's Word. However, that does not leave logic or reasoning out of the picture. Ministers use logic and reasoning in their sermons all the time. You can find examples of logic or reasoning in our confessions. All of this serves to indicate for us that logic is a tool for communication and persuasion. Moreover, just as there are laws (or truths) in mathematics (such as 2+2=4) and laws of physics, so also there are laws of logic. Logic is not a matter of human convention, something that people have agreed upon, but it is part of the created order. Laws of logic are absolute, not relative. Therefore, in order to communicate the gospel effectively, and more to our purposes, to defend it, it is necessary to know a few basics about reasoning.

The most important basics to know are the informal fallacies of reasoning. Informal fallacies are errors in reasoning which have to do with content, rather than with structure. Since these are very common and easy to diagnose, I'll go over a few here with you. The purpose is so that not only do you watch out for these errors in your own reasoning, but also so that you can detect them in the reasoning of others and then humbly and lovingly point them out.

Ad Hominem Abusive⤒🔗

This error in reasoning is by far the most common and the one that unbelievers tend to exploit the most in their contacts with Christians. The expression ad hominem comes from Latin and simply means to the man. When you add the word abusive, it does not take much imagination to see what happens. The argument shifts away from the issue at hand and instead it attacks the other party's character. We saw this error in the evaluation of Templeton's book. He attacks Christians and says that they are quite a bunch of hypocrites. Templeton tells a story of how he and another minister would go after evangelistic crusades and visit prostitutes. Not only that, but look at how much misery Christianity has brought into the world! In arguing this way, Templeton is shifting the attention away from the issue at hand (whether Christianity is to be believed). He is guilty of the abusive ad hominem fallacy. But we must be equally careful not to fall in the same trap. Christians could just as easily respond by pointing to all the atrocities of unbelievers or so-called atheists and agnostics. There is plenty of mud around if one knows where to look for it. But this type of argumentation is immoral and does not befit those who are to sanctify the Lord in their hearts.

Poisoning the Well←⤒🔗

This is a variation of the ad hominem fallacy. The name for this fallacy comes from a debate between John Henry Cardinal Newman (a Roman Catholic priest) and Charles Kingsley (a Protestant and a novelist). Kingsley suggested that Newman did not give very much weight to the truth, since he was a Roman Catholic. Newman objected that this suggestion poisoned the well of the debate so that no one would now take him seriously. Another example would be to say something like, "Why should I expect you to agree with what I'm saying? You're an unbeliever." Making a statement like that poisons the well, it makes discussion and debate nearly impossible. Christians should be charitable in their conversations with unbelievers - not just for the sake of the unbeliever or because poisoning the well is an error in reasoning, but more importantly because you simply don't know whether or not the Holy Spirit is working for the redemption of that person.

Hasty Generalization←⤒🔗

In one form or another, I'm pretty sure most of us know how this error works. "I once worked with a (insert some ethnic group). They're all lazy, incompetent, and greedy - every single one of them." With this fallacy, a single isolated case or small number of cases, is used as the basis for a general conclusion about every case. The argument assumes that what is true in one case will be true in every subsequent case. An unbeliever might use the error in this way: "I know a Christian, and I wouldn't trust any of them. This Christian, he steals from the bank deposits, cheats on his taxes, speeds on the freeway and yells at his wife. You just can't trust Christians and so I wouldn't want to be one." If you lurk on an Internet newsgroup that discusses the defense of the Christian faith or atheism, you'll see that this fallacy creeps up time and again. Christians must also be careful about making hasty generalizations about atheists such as thinking that since they don't believe in God, they're all Stalins and Hitlers or axe-murderers. One can make generalizations in apologetics, but they must be grounded on facts and must be relevant to the argument.

False Cause←⤒🔗

This argument says that some event has caused another event when no such relationship has been proven. This error is not so common as it once was, but it is still good to be familiar with it. An example would be that since the Roman empire disintegrated after the appearance of the Christian faith, the Christian faith is to be blamed for its demise - the argument to which Augustine responded in his book The City of God. Of course, it may very well be that such was the case, but then one must prove it with evidence. From our own perspective, we might commit this error if we make this simple statement without proving it: "Morality and the Christian character of our civilization disappeared after the acceptance of evolutionary theory. Therefore, the theory of evolution is to be blamed for the situation we're in today." Again, this could very well be true, but then you have to show how this is true; you must prove it with further evidence or argumentation.

Equivocation←⤒🔗

When one equivocates in this argument, he changes the meaning of a keyword in the middle of the argument. This is slightly more complicated than the other fallacies, but an example may make it clear for you. The issue of capital punishment was debated again recently with the case of Stanley Faulder in Texas. In these debates, people who call themselves Christians sometimes appeal to the sixth commandment. They say that this commandment says that we are not to kill, therefore we may not put criminals such as Mr. Faulder to death. God says we can't kill, therefore we don't kill. There is a legitimate appeal to authority here, but even apart from the other Scriptural evidence in favour of capital punishment this argument is fallacious. The problem rests with the word "kill." Most modern translations now (rightly) translate that word as "murder." The sixth commandment really says that we are not to unlawfully kill someone, or murder. It is not an absolute injunction against killing in general. The argument against capital punishment fallaciously equivocates (changes the meaning) of "kill." God says do not kill unlawfully, but the Texas authorities are lawfully appointed to bear the sword against evildoers. The lesson here is that in our arguments we must use all the words in exactly the same sense.

Appeal to Authority←⤒🔗

"Why do you believe in the resurrection of Jesus Christ?" "Because the Bible tells me so." Many, if not all, unbelievers would say that this is a fallacious appeal to authority. However, not all appeals to authority are fallacious. As long as the authority to whom we are appealing is a reliable and competent one, we may justifiably appeal to him or it in our arguments. With the example above, the one claiming the Bible as his authority on the subject of the resurrection must defend its authoritative character and show that the Bible is absolutely reliable. Unbelievers themselves usually do not make appeals to one authority, but they do sometimes to a great number. This is sometimes called the argument by consensus. Millions of North Americans aren't Christians, therefore the Christian faith can't be the right one to believe in. Of course, we recognize that the truth of something does not depend on how many people do or do not believe in it. One could just as well argue that millions of North Americans are (or claim to be) Christians, therefore the Christian faith is the right one. It is far better and more God-honouring to discuss the inherent character of the Christian faith then it is to get caught up in debates about how many people do or do not believe it.

There are many more informal fallacies which we could discuss, but this gives you a brief overview of what to watch out for as you continually prepare yourself to be always ready to give an answer or a reasoned defense. The Lord God wants the best from His people and that includes how they go about defending the Christian faith. The holy priesthood of believers must be knowledgeable concerning Scripture, but they must also be able to present and defend the truths of Scripture in a coherent and reasonable way.