I’d Like to Have an Argument, Please.

Author Greg Koukl Published on 07/01/2002

A solid argument can be built just like a solid house: walls first, then the roof. Here’s a building plan, plus three ways arguments collapse.

I want to teach you how to assess a basic argument. How can you know if an argument is a good one or not?

There’s no magic to this. The tools of thinking are simple ones. Anyone can employ them skillfully with a little practice. If you have the right equipment you can make a lot of progress even if you don’t consider yourself an intellectual whiz-kid.

Think of an argument like a simple house, a roof supported by walls. The roof is the conclusion and the walls are the supporting ideas. In the lingo of logic, the walls are called premises and the whole structure of the building is called a syllogism.

Syllogisms have a particular form and contain certain facts. When the form is right and the facts are true we say that the argument is sound, that the walls are strong enough to support the roof. The conclusion is true, resting securely on its supporting foundation.

Our goal in clear thinking is to see if the walls are solid or can be knocked down. If the walls go down, the roof goes flat and the argument is defeated.

A House with No Walls

First, an observation. Some arguments are not really arguments at all. In terms of our house illustration, many people try to build their roof right on the ground. Instead of erecting solid walls—the supporting ideas that hold the conclusion up—they simply assert their conclusion and pound the podium.

An argument is different from an assertion, though. An assertion simply states a point. An argument gives supporting reasons why the point should be taken seriously. The reasons become the topic of mutual discussion or analysis. But if there are no reasons, there’s little to discuss. Opinions are opinions, not proof. A mere point of view cannot be taken seriously as worthy of belief. That requires reasons.

Roofs are useless when they’re on the ground. In the same way an assertion without evidence doesn’t do any work. I frequently get calls from people who think they’re giving me an argument, when all they’re doing is forcefully stating a point of view. They sound compelling, but a closer look reveals an emperor with lots of bluster, but no bloomers. My job is to recognize that the roof is laying flat on the ground and simply point it out.

If you find yourself stymied in a discussion, you may be looking for an argument that’s not there. Ask yourself, “Did they give me an argument or just make an assertion?” If the latter is true then say, “Well, that’s an interesting opinion. What’s your argument? Why should I believe what you believe? How did you come to that conclusion? Give me your reasons.”

Don’t let them flatten you by dropping a roof on your head. Make them build walls underneath their roof. Ask for reasons or facts to support their conclusion.

Three Ways an Argument Can Go Bad

Any real argument—as opposed to an assertion—has three parts. It has a particular form, it affirms particular facts, and it uses particular words or terms to make its point. When an argument goes bad, the problem is either in the form, the facts, or the terms.

First, an argument’s form can be bad. Let me give you an example. Take this syllogism: “All men are cheerful. John is a man. Therefore, John is cheerful.” This is a simple argument containing two statements (premises) and a conclusion. The conclusion is dependent on the first two statements. The first is the major premise—all men are cheerful. The second is the minor premise—John is a man. The final statement is the conclusion—John is cheerful.

Notice the form of this argument. It’s clear that if the facts of the first statement are true, that all men are cheerful, and if the facts of the second statement are true, that John is a man, then the conclusion follows naturally. If you accept the truth of the first two statements, the truth of the third is automatic. One “follows” from the other. When the form is correct we say the argument is “valid.”

What about this one: “All men are cheerful. Jane is not a man. Therefore, Jane is not cheerful.” A moment’s reflection shows this doesn’t work. Even if it were true that all men are cheerful and Jane is not a man, it still wouldn’t follow that Jane is not cheerful. Women can be cheerful, too.

We use the term “fallacy” to describe an argument that has a faulty construction. There are different types of fallacies listed in logic books, and I won’t detail them here. Many of them, though, are obvious upon a little reflection. Just ask yourself, “Does it follow that because A and B, therefore C?” Does it follow that (A) because all men are cheerful, and (B) Jane is not a man, that (C) Jane is therefore not cheerful?

When the form is bad—when the conclusion does not follow from the premises—it’s called a non sequitur, Latin for “it does not follow.” Non sequiturs cannot be trusted. It may be Jane is not cheerful, but you can’t know that from the information provided.

Even when the form is right there still may be problems. Facts can also make an argument go bad. Accurate form (a valid argument) does not guarantee that the statements themselves are accurate. What if it’s not true that all men are cheerful? Maybe some are gloomy. What if John is not a man, or not even human? Maybe John is a robot or the name of Socrates’ pet Schnauzer.

Take the argument, “All unicorns live in Ireland. Pegasus is a unicorn. Therefore, Pegasus lives in Ireland.” Acknowledging that the form is valid (it is) doesn’t at the same time commit you to the existence of unicorns or tell you anything about where they live. The factual questions about unicorns is a separate issue.

If the facts in the statements are wrong, then the argument still fails even though the form is right. Clear thinking requires we look closely at the facts as well as the form. The statements themselves must be true.

The third way an argument can go wrong is in the terms. The meanings of the words may not be clear. This is called “equivocation.” Basically, equivocation means a vagueness, ambiguity, or uncertainty. If somebody states her opinion very clearly and then under challenge becomes less sure of her position, we say she’s equivocating. She waffles; she’s uncertain.

Sometimes words are equivocal. They are unclear, uncertain, or may have multiple meanings that become confused with each other in the discussion. This creates problems for an argument.

Look at this example: “All men are cheerful. John is a man. Therefore, John is cheerful.” The word “man” may be equivocal. It’s unclear whether “man” means a grown male or simply a member of the male gender. The phrase “all men are cheerful” could refer to all adult males and exclude boys.

Our argument would falter through equivocation if we meant this: “All men [adult males] are cheerful. Little Johnny is a man [male gender]. Therefore, little Johnny is cheerful.” See the problem? What is meant by “men” in the first sentence isn’t the same as what is meant by “man” in the second sentence. There is confusion—equivocation—on the term “man.”

Here’s a real-life theological example: “Jesus is God. Mary is the mother of Jesus. Therefore, Mary is the mother of God.”

The form here seems correct—the conclusion follows from the premises. It also seems that the individual statements are true. But something’s wrong here. God is not the kind of being that has a mother. Where did we go wrong?

The problem becomes more obvious when we take it a step further: “Mary is the mother of God. God is a trinity. Therefore, Mary is the mother of the Trinity.” This, of course, is patently false. But why is there a problem if the form is sound and the facts are in order?

The problem lies with the terms. There’s an equivocation here on the phrase “Jesus is God.” Jesus is a very unusual individual. Yes, He is God, but He’s also fully human. Jesus is one person with two natures, the nature of God and the nature of man.

When we say Jesus is God, we are not saying His humanity is divine. That would be a contradiction. We are saying He is God in that He has a divine nature. Mary is the mother Jesus in the sense that she’s the mother of His physical body. She is the mother of His humanity, not the mother of His divinity.

Equivocation on these terms—the lack of clarity—makes false a seemingly sound conclusion. The facts are right. The form is right. But the conclusion is false because the meanings of the terms are ambiguous. They’re equivocal.

Recently I got a call from a gentleman who said, “Jesus is God. God is a trinity. Therefore, Jesus is a trinity.” He thought he constructed his argument right, but clearly the conclusion is false. Therefore there must be something wrong with the facts. Either Jesus is not God or God is not a trinity. Of course, this was his point. He was challenging the notion of the Trinity on logical grounds.

My caller’s error, though, was not in the form or the facts of the argument, but in an equivocation in the words. When Christianity teaches that Jesus is God, it doesn’t mean that Jesus and God are identical. Jesus has the nature of God, but He is not everything that God is. God subsists in three persons; Jesus is only one person.

What was missing here was a clarification of terms. The clarification had to be made—and the equivocation removed—for this attack on the Trinity to be defeated.

Some of the assessment of an argument is based on the clarity of the concepts involved. This is why precision with words is critical to clear thinking.

Invisible Walls

Sometimes it’s very difficult to assess an argument because the full form of the argument is not stated. The elements aren’t listed one, two, three as they were above. Some of the parts are taken for granted—“understood” by the participants—in the process of conversation. This streamlines conversation, but it can also allow bad facts to go undetected.

Once a homosexual said to me, “Jesus never condemned homosexuality.” Though this is only one sentience, it’s actually a full argument in shorthand, streamlined for brevity. The conclusion didn’t need to be stated. I got the point. I was wrong for attacking homosexuality on moral grounds. Because Jesus never condemned homosexuality, it is therefore morally acceptable behavior.

Notice, though, that the conclusion is not the only thing taken for granted here. The minor premise is stated and the conclusion is assumed, but what of the major premise, our first step in the argument? The unspoken major premise—the invisible wall holding up this argument—contained a serious flaw that went undetected.

We discover the flaw by asking what kind of major premise is needed to make this argument work. The full argument would have to look something like this: Whatever Jesus did not explicitly condemn is morally acceptable. Jesus never explicitly condemned homosexuality. Therefore, homosexuality is morally acceptable.

The form of this argument is good; nothing amiss there. But look closer at the major premise. Its facts are bad; this statement is clearly false. It doesn’t seem to be true that whatever Jesus doesn’t directly condemn is morally acceptable. Jesus never condemned slavery, child abuse, wife-beating, or gay-bashing, but that proves nothing.

Many Christians are caught flat-footed here, sensing something is wrong, but not knowing what it is. Sometimes we have to look more closely and identify the unspoken premise. That can be done by asking a simple question: “Are you saying that if Jesus doesn’t specifically condemn something, then He condones it?” When they say no (and they must, because such a view is untenable), ask, “Then what’s your point?” Don’t get into a fuss. Just ask the question calmly and directly. The silence that follows proves the game is up.

A Jehovah’s Witness once called me and said, “The Trinity isn’t mentioned in the Bible.”

The unspoken point was obvious: “Therefore, the Trinity is not biblical.” I asked, “Are you saying that anything not specifically mentioned in the Bible cannot be true?” (the invisible wall).

He was in trouble here because lots of things aren’t mentioned specifically in the Bible that still find support in the Scripture. The word “monotheism” isn’t in the Bible, or the word “Jehovah,” as a point of fact.

“No,” he answered.

“Then what’s your point?” I responded, and the argument was over.

Often times the flaw in an argument—the “fact” that’s wrong—is hidden in an unspoken assumption that your opponent takes for granted. Kick the unspoken premise into the open. Usually that’s all that’s needed for the whole structure to come tumbling down.

The Obligation of Reason

To assess a genuine argument and not a mere assertion, examine the structure. Observe the form of the argument. Examine the facts. Look for hidden statements that may not have been expressed. Finally, examine the terms to see if there’s any equivocation, any ambiguity or lack of clarity.

If the argument is sound—if the form is valid, the facts accurate, and the terms clear and precise—then the conclusion is true. Period. In fact, the conclusion is irrefutable; it’s not even possible to be mistaken.

This demonstrates the compelling nature of rationality. There is a bomb-proof quality about deductive logic. If one is faced with a logically valid argument with clear terms and accurate facts, he has a rational obligation to believe the conclusion, even if he doesn’t like what he finds. This is called intellectual honesty.

Rationality has nothing to do with what we like; it has to do with what is true. That’s why it’s such a useful tool for all who are interested in knowing the way the world really is.

A solid argument can be built just like a solid house: walls first, then the roof. Here’s a building plan, plus three ways arguments collapse.