Fallacious Logic: A Brief Overview

The most deceptive and unreasonable types of arguments are the ones that use faulty logic. In this document, I hope to show some of the most common and misunderstood arguments that anyone should know.

REASONING

All logical fallacies use some sort of reasoning in order for the argument to seem more evident. Even sound reasoning can be a victim of fallacious arguments. The purpose of this overview is to get a better understanding of what the actual reasoning is.

Occam’s Razor:

Basically, Occam’s Razor (also spelled Ockham’s Razor) is the philosophical and scientific rule that simple explanations should be preferred over more complicated ones, and that the explanation of a new phenomenon should be based on what is already known. If you can not already guess, this reasoning can be twisted to bias one’s illogical argument. For example, a Creationist might use Occam’s Razor in his or her favor. “Evolution, Astronomy, Cosmology, Physics, and the rest of the scientific schools of thought are so complex. Occam’s Razor shows that the simpler notions are preferred, therefore God did it.” In the case of Occam’s Razor, simpler does not mean “a shorter explanation”, it more formally means “entities must not be multiplied beyond necessity”. Another explanation of a fallacious application is “There are over 90 known elements, but ancient alchemists only knew four. Therefore, the ancient alchemists are correct.” Occam’s Razor is misused in this sense because one is more accurate than the other. Occam’s Razor is used when two or more theories are equally accurate.

Abductive, Deductive, and Inductive Reasoning:

In short, abductive reasoning is deducing an effect to a probable cause. For example, if my backyard is wet in the morning, I can deduce that it rained. This may be misused by creationists when they use the analogy of complex human bodies seemingly being designed such as an intricate pocket watch.

Deductive reasoning is probably more familiar to you because of Sherlock Holmes. For example, I know that I am going to receive three different colored balls; one red, blue, and green. I am given the blue and green balls first, so I may deduce that the next ball is going to be red.

Inductive reasoning is deducing general principles from specific examples. For example, if I find big leaves from my neighbor’s back yard in mine, I may conclude that the trees in my neighbor’s backyard have big leaves. I know there are small leaved trees, but I do not expect to see them in my neighbor’s back yard. You may already have found a way of this reasoning being fallacious, and you may be right; inductive reasoning can never lead to a definite conclusion (except in math).

FALLACIES

There are several logical fallacies that one may use in order to prove an otherwise improvable notion. I will only write about a few well known fallacies in this document.

Post hoc ergo propter hoc:

What that statement literally means is “after this therefore because of this.” The structure is simply “A happened, and then B happened. Therefore, A caused B.” I once heard of the example for this fallacy about an alien visiting earth. It goes something like this: “An alien from outer space visits earth and lands near two churches which have bell towers. Every day at noon, one of the bells of the tower rings a few seconds before the other bell. The alien believes that the first bell caused the other bell to ring.” As you and I know, a bell does not cause another bell to ring, but the alien does not know this. One way to get a definitive answer is to stop the first bell from ringing and see if the second bell will ring at noon without the first. The same type of manipulation is used in science.

Argument from Incredulity:

The Argument from Incredulity (also known as the Argument from Ignorance) usually means that one draws a positive conclusion because he or she can not imagine the converse being true. For example, “I can not imagine the toast burning in the toaster without a toast burning fairy, therefore there are toaster fairies.” This can also be used as “You can not disprove this notion, therefore it is true,” or “You can not prove it, therefore it is false.” There is, however, an exception to this rule. This argument can not stand alone without some logic, it would need further evidence. For example, “This is an abandoned train station, yet the lines are still open. I see a train approaching. Therefore, this train will not stop at this station.” Like I stated before, the argument can only make sense if evidence is provided.

Argument from Misleading Definition:

This fallacy seems pretty self-explanatory. When someone misuses a definition in an argument to work in their favor, this would be considered an Argument from Misleading Definition. “The Theory of Evolution is not true because a theory is just a hypothesis,” is a common use of this argument. If there ever is confusion of a definition of a word, it is best to consult a dictionary.

False Dichotomy:

In short, a False Dichotomy is the type of argument where someone presents only two options and makes a false conclusion when in fact there are more options. For example, “You are either with us or against us” is a False Dichotomy because you might not agree with their side or the opposing view. Not every argument where two options are presented are False Dichotomies, sometimes there are actually only two options.

Begging the Question:

A general structure of this argument goes like this: A implies B, B implies A, therefore A. Here is a simpler version: “The Bible is inerrant. The Bible says that God exists, therefore, God must exist.” Sometimes this may make sense, such as in this example: “You said you were at the market. Your friend said that you were at work. This begs the question, is one of you lying or are both of you?” In this case, there is no argument, just a question.

Strawman Fallacy:

The origin of this fallacy from an imaginary instance where two people argue, one builds a straw dummy of his or her opponent, destroys the dummy, then claims to have defeated the opponent.

The Strawman argument is when someone misrepresents an opponent’s argument, attacks the weaker argument, and claims to have defeated the opponent. I once saw a skit on television where two lawyers are talking to a man in court, asking questions like “Would you rather stomp on an old lady to death or a small dog?” The man would be forced to answer the question and would reply “Okay. I’ll kill the dog.” The lawyers continue to say that the man has murderous intents and can not be trusted. Other examples of the Strawman Fallacy are misleading definitions, putting words into the opponent’s mouth, and quote mining (misquoting, or quoting out of context).

MISLEADING CLAIMS

The following are not used as much as fallacies but to mislead.

The God of the Gaps:

In short, when an event or claim can not be proven scientifically, God is used as the answer, hence God of the Gaps. “I can not understand how an eye or insect wings could have evolved, therefore it was God,” “No one knows how Stonehenge was built, therefore it was aliens,” or “I hear ambiguous noises coming from this old house, therefore it is infested with ghosts” are all misleading claims.

Anecdotal Evidence:

Anecdotal Evidence (also called Unjustifiable Claims) is an explanation of events used as “evidence” to “justify” a claim. “I saw a UFO, therefore my claim is evidence,” “I was visited by my father through a clairvoyant, therefore clairvoyants’ practices are practical,” or “This little boy is claiming to have memories from a past life, therefore reincarnation is true” are examples of Anecdotal Evidence. Even if the events occurred, it is not evidence because they are not justifiable (even if it happened).

Cherry-Picking:

Cherry-Picking is sometimes used to disprove someone’s claims using only one piece of data and ignoring other’s data. For example, creationist Jim Pinkoski claimed that older fossils are larger, citing larger than modern dragonflies, beavers, cockroaches and other animals in order to prove the claim made in Genesis 6:4 stating that animals were larger before the flood. Cherry-Picking can also be used as Quote Mining. Some creationists Cherry-Pick Charles Darwin; they only read one or two lines, but do not read the entire paragraph or paragraphs where the actual context is different. Here is a link to a video where a creationist Quote Mines Charles Darwin. Please watch it.

Logical fallacies can, have, and definitely will be used to prove an otherwise illogical point. I urge you to follow this link on SkepticWiki.com and scroll through the other fallacies that I have not described. If you know these fallacies, it will be much easier to have a logical conversation or argument.