Logical Fallacies

Logic can be a valuable tool for Christians to defend their faith. But mistakes in reasoning can derail even the best argument.

The faulty appeal to authority is, in a way, the opposite of the ad hominem fallacy. Whereas the ad hominem fallacy denies a claim based on the person making it, the faulty appeal to authority endorses a claim simply based on the person making it. Essentially, the faulty appeal to authority is the argument that a claim is true simply because someone else believes it.

The basic structure of the argument is this:

  1. Bill believes X.
  2. Therefore, X is true.

Of course, it is almost never stated this explicitly. Often, the person to whom the appeal is made is considered highly esteemed for one reason or another. But the truthfulness of the claim at issue is not necessarily relevant to the popularity of the individual making the claim.

In the origins debate, the faulty appeal is often to someone who is considered an expert on a particular topic—a scientist or perhaps a theologian. For example, “Dr. Bill has a PhD in biology, and he believes in evolution.” The unstated conclusion is that evolution must therefore be true or is at least likely to be true. But such an argument is fallacious. After all, we could equally point out that “Dr. Dave also has a PhD in biology, and he believes in biblical creation.” The fact that other experts on the topic draw the opposite conclusion should reveal the vacuous nature of the evolutionist’s argument.

Another example would be this:

“Jim has a doctorate in theology, and he says it’s okay to believe in evolution and the Bible.”

Again, we could certainly find many qualified theologians who would state the exact opposite. While it is okay to consider what a theologian has to say about the Bible, it is infinitely more important to consider what the Bible actually states!

If an expert on U.S. law claimed that the Constitution does not contain the phrase “We the people,” would that make it so? We could easily refute his claim by simply reading from an actual copy of the Constitution. The fact that he is an expert does not override the evidence.

Not all appeals to authority are faulty appeals to authority. It is legitimate to consider the opinion of an expert on a particular topic. None of us has the time or the ability to verify each and every truth claim that has ever been made. We can and should rely upon the expertise of others at times. So, when does the appeal to authority become a fallacy? It seems there are three common ways in which this occurs:

  1. Appealing to an expert in an area that is not his area of expertise. Our hypothetical Dr. Bill may indeed have a PhD in biology—and that qualifies him to say something about how organisms function today. But does knowledge of how things work today necessarily imply knowledge of how things came to be? This is a separate question. The experiments Dr. Bill has done and the observations he has made have all taken place in the present world. He has no more direct observations of the ancient past than anyone else today.1 The question of origins is a history question that deals with worldviews. It is not really a biology question, and, so, Dr. Bill’s opinion on the topic of origins isn’t necessarily any more qualified than any other opinion.
  2. Failure to consider the worldview of the expert and how this might affect his interpretation of the data. We all have a world-and-life view—a philosophy that guides our understanding of the universe. When we interpret scientific and historical evidence, we use this philosophy to draw conclusions.2 The fact that Dr. Bill believes in evolution means that he is predisposed to interpret the evidence in a particular way. (My point is not to fault him for this; everyone has biases. Rather, we should simply be mindful of what his biases are). A creationist with the same credentials might draw a very different conclusion from the same data. So, while I may put confidence in what Dr. Bill says about the structure of a particular protein that he has studied under the microscope, his bias against biblical creation means it would be unwise for me to trust his opinions on questions of origins.
  3. Treating a fallible expert as infallible. We should also keep in mind that even experts do not know everything. They can make mistakes even in their own field. Some new discovery may cause a scientist to change his mind about something that he thought he knew. So, at best, appealing to an expert yields only a probable conclusion. It would be fallacious to argue that something definitely must be true simply because a (fallible) expert believes it.

Of course, if the expert had knowledge of everything and never lied, then there would be no fallacy in accepting his statements as absolutely true. In fact, it would be absurd to not do so under those circumstances. The Bible claims to be such an infallible source—a revelation from the God who knows everything and cannot lie.3 Thus, there is no fallacy in appealing to Scripture as absolutely authoritative. Some evolutionists have mistakenly accused creationists of committing the faulty appeal to authority on this very issue.

Another type of faulty appeal to authority is the appeal to the majority. This is when a person argues that a claim must be true simply because most people believe it. But, of course, just because a majority of people believe something does not make it so. History is replete with examples of when the majority was totally wrong. Truth is not decided by a vote, after all.

This fallacy is so obvious it is hard to believe that people would fall for it. But there is something very psychologically seductive about the appeal to the majority. We are inclined to think, “How could all those people be wrong?”4 Of course, it could well be the case that many people in that majority are convinced of the claim at issue for exactly the same reason: because all the other people in that majority believe it (which is no logical reason at all.)

The appeal to the majority is often combined with the appeal to an expert—an appeal to the majority of experts. Evolutionists often commit this double-fallacy; they try to support their case by pointing out:

“The vast majority of scientists believe in evolution. (Therefore, evolution is very likely to be true).”

However, simply adding two fallacies together does not form a good argument! Again, we could point to many historical examples of cases where the scientific consensus was dead wrong. Yet, people continue to perpetuate this fallacy.

We sometimes hear phrases like

“According to mainstream science . . . ,”
“The scientific establishment . . . ,”

or

“the scientific consensus is . . . ,”

as an alleged proof of a particular claim. Another example is this:

“Creationists teach that the world is roughly 6000 years old, but the majority of scientists disagree.”

This sentence is true, but the unstated conclusion is that we must accept the opinion of the majority of experts—which is logically fallacious.

As with a single expert, it is not fallacious to consider the opinion of a group of experts. However, as before, we should consider whether they are qualified in the issue under investigation, be mindful of their worldview and biases, and keep in mind that they are fallible people with finite knowledge.

I believe that God gave people different interests and is pleased when they study hard and develop expertise on some aspect of His creation. It is commendable to esteem the opinion of experts, provided that we are discerning and never regard fallible human opinions above (or equal to) the authoritative Word of God.

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Footnotes

  1. For some reason, it is common for people to think that paleontologist and geologists study the past. But this is not so. Rocks and fossils exist in the present (otherwise we wouldn’t have access to them). Although there is nothing wrong with speculating about past events (e.g., how fossils or rocks formed) and then testing the plausibility of such models with experiments in the present, we should keep in mind that the past is never actually observable or open to scientific investigation. Back
  2. Some evolutionists might claim that they have no philosophy—that our interpretations of evidence should be “neutral” and unbiased. But this is a philosophy in and of itself, albeit a very bad one since it is self-refuting. Back
  3. Colossians 2:3; Titus 1:2 Back
  4. Sin is the answer to this question. All people have a sin nature. Those who have not had their minds regenerated by the Holy Spirit are not capable of drawing correct conclusions on spiritual matters (1 Corinthians 2:14). The unbeliever is not a neutral, objective observer. He is rebellious and strongly motivated to reject the biblical God (Romans 1:18–20). Back