If you have not read my Introduction to Logic, you may want to do so now and then read my Basic Logic Structure post as well.

So how do we spot logical fallacies and prove untrue statements wrong? Refer to scripture!

We’re going to employ the biblical practice of answering a fool according to his folly, lest he be wise in his own eyes. It is described in Proverbs 26:5 and is a way of showing someone an argument ad absurdum or proof by contradiction. What you do is start with the beliefs of a viewpoint, and then follow those views logically to their conclusions or deductions. If you find a contradiction to the original assumption (or another known truth) or an obvious absurdity (usually defined by a contradiction to known truth) then you know you can deny the original assumption.

Let me show you by example; here is a logical argument.

1. Assume that 2+2 = 5.
2. Add to that the knowledge that 2+3=5
3. Subtract “1” from both sides of the equation, 2+3-1=5-1
4. Conclude that 2+2=4

And we have a contradiction! As soon as we find a conclusion which logically follows from the argument, but contradicts another known fact, (or in this case, the assumption), we know that at least one of our assumptions must be false. So the assumption that 2+2=5 is FALSE! The point is this: if your assumption leads to a contradiction itself, then it must be false. How does this relate to Proverbs 26:5? The meaning of this verse is that we are to help to show people where their statements of belief logically lead. So if a person tells you they believe in anything at all, and you know that belief to be false, you can show them through sound logic that their belief leads to a contradiction. Here is a good example: there are many who claim today that ALL religious views are true. Well, if this is true, then biblical Christianity is true. Biblical Christianity claims that Jesus is the only way to God and that all other religions are false. This is clearly a contradiction to the first statement (assumption) that all religions are true. All religions cannot be true and at the same time only one religion be true. In many cases, you will find that the person did not believe their original statement was an assumption. They likely believe it is a fact, or consider it axiomatic, or self-evident. Often people will get very angry when you do this, so you must do it with meekness and fear. But it is an important task. An equally valid way to proceed would have been to prove to the person they really cannot believe what they said about all religions being true. You can point out that Christianity states only Christianity is true, and that by their own admission, they believe Christianity to be true, which then contradicts their stated belief.

I have done this with postmodernists as well. Often you will hear someone say that they don’t believe it is anyone’s right to “push their beliefs onto others.” Interestingly enough, you can point out that if they TRULY believed this, they would never actually tell you, because in the act of telling you, they are pushing their belief onto you! An honest pacifist or postmodernist must be careful, because that worldview is so contradictory that they can hardly leave the house without contradicting their own stated beliefs.

The other way to “show a fool their own folly, lest he be wise in his own eyes” is by taking the person’s argument logically to the point of absurdity. This is another valid logical practice whereby you show that a person’s beliefs logically lead to absurdity. This is called a Reductio ad absurdum and is more common in mathematical proofs than in daily speaking engagements, but can be effective nonetheless. Any argument that leads the assumptions to absurdity, ultimately only leads to absurdity because it contradicts a known fact. But sometimes the result is so absurd that it doesn’t deserve further discussion. Usually, it is obvious that a logical conclusion is absurd, but sometimes we can’t spot the fallacy or recall the known fact that is being contradicted. You will be able to use sound logic to help people to see error, and to find errors in your own beliefs. Just remember that a lot of people do not enjoy being told they are wrong, so do this in love, with a spirit of humility. The goal isn’t to be argumentative or to “win,” but rather to be boldly proclaiming truth and winning souls for Christ. So don’t back down or compromise, but always remember that people can be sensitive, and that many folks hold very dear to themselves the things they believe. Dear Christian, you ought to also do so! For if someone was to shake the foundation of your belief, it should cause much fear and shuddering, for it is your only hope. Remember this when you are shaking the foundations of other’s hope.

The first part of the verse for this week is advice as to how NOT to argue. What this verse is saying is that we ought not to argue following the assumptions and rules of others. A good example is that a Christian should never allow for an argument that isn’t allowed to use the bible. By throwing away the most important assumption of your argument, what do you expect to prove? This refutes of the neutrality fallacy. Many people believe you can be neutral to the Bible, that is, that there is a platform on which you can stand where you are neither standing for God’s Word, nor are you standing against it. This is a fallacy for the exact reason that if the Bible is true, then to argue without it would be to be choosing not to use your most valuable weapon and only essential weapon! If somehow your assumption that you can rely on biblical authority is not true, then you will lead yourself to contradiction or fallacy.

One of the reasons we make sure to don’t answer a fool according to his folly, is that it usually leads to self-contradiction and we do not want to suffer that contradiction. So for example, if a person tells you that you shouldn’t force your beliefs on others, you can tell them that based on their own stated values, they ought not force that belief on you (answer, lest he be wise), but you may also proceed in stating you personally do not subscribe to that belief, so you are not in error to continue sharing your faith (don’t answer, lest you be like).

I wrote a blog about judging a few months ago that you might read with joy if you want. One of the points I made is that if a person ever calls you judgmental (in the sense that they are telling you that you are doing something wrong by judging), you can very easily respond by letting them know that their act of accusing you of judging is judgmental, and that if they are allowed to do it, you should be allowed as well. And if they ought not to judge, then they ought not to tell you not to. You can see that it is actually impossible to ever hold the positive that “there is no absolute truth” or “people should never judge” since these ideas are clearly so self-contradictory. If there is no absolute truth, how can I ever state truthfully that there is no absolute truth? Absurdity.

The idea is this, when you make a positive argument, you always rely on your presupposition that God is, that He spoke through His Word, and that His Word is true. (Hebrews 11:7) When you are evaluating the argument of another, you can politely state that you deny their assumptions, so their deductions are invalid to you, (Proverbs 26:4 “Don’t Answer”), then you can confidently show them that their assumptions lead to foolishness (Proverbs 26:5, Proverbs 14:12). This is true of both Christians and non-Christians with whom you may discuss doctrine, or good teaching. Your reliance on God’s Word as your ultimate authority will be your only chance to avoid false presuppositions which will cause you to fall on your face, and it just might be the impetus for a person deciding to read it with the assumption that it may be true.