Critical Thinking: The Ten Commandments

As promised, we are going to be diving into some of the most common logical fallacies used in debates.  Put simply – a logical fallacy is an error in reasoning.  This differs from a factual error, which is simply being wrong about the facts.  To be more specific, a fallacy is an “argument” in which the premises given for the conclusion do not provide the needed degree of support.  Logical fallacies are most often found in debates centered on politics, religion, or social problems, but can be used in almost every subject.  Being mindful of logical fallacies is one of the key components to critical thinking.  It is important to be aware of them when presenting your own case, as well as spotting them in others’ arguments.

We’ll start by going over the “Top 10” fallacies listed above in greater detail.

Ad Hominem

Translated from Latin to English, “Ad Hominem” means “against the man” or “against the person.”  This is when the person or source of information is attacked rather then the information being presented.  Examples:

Person A:  “You shouldn’t give baby formula to infants because it is made with soy, which has been shown to have adverse effects on children.”                                                                                                                         Person B:  “You don’t even have children, so what would you know about raising them!”

Person B ignores the argument, focusing only on the arguer.  Whenever an arguer cannot defend his position with evidence, facts or reason, he or she may resort to attacking an opponent either through labeling, straw man arguments, name-calling, offensive remarks, or anger.  Another example where the source of information is attacked:

Person A:  “CNN reported that gun violence has increased in the last ten years”                                                                                                                                       Person B:  “CNN is a liberal news site!  You can’t trust anything they say”

The reason why an Ad Hominem is a fallacy is that the character, circumstances, or actions of a person or source do not (in most cases) have a bearing on the truth or falsity of the claim being made (or the quality of the argument being made).

Straw Man

A straw man argument is one that misrepresents a position in order to make it appear weaker than it actually is, refutes this misrepresentation of the position, and then concludes that the real position has been refuted. Examples:

Person A:  “I don’t believe in an gods, including the Christian one.”       Person B:  “So, you have no objective base for morality then?  Basically, there is no right or wrong and anything goes?”

Person A:  “I believe we need to cut military spending and put that money towards education health care.”                                                               Person B:  “Oh, you want to leave our country defenseless from invasions from other countries?”

These are fallacies because the position that has been claimed to be refuted is different to that which has actually been refuted; the real target of the argument is untouched by it.

Straw men arguments can often take the form of caricatures – representing a group or person using exaggerations, stereotypes, and falsehoods.  Example:

Hasty Generalization

A hasty generalization is committed when a person draws a conclusion about a population based on a sample size that is too small.  It is important to have samples that are large enough when making a generalization.  Example:

Person A:  “Smoking has been proven to have a negative effect on ones’ overall health”.                                                                                               Person B:  “My uncle smoked two packs a day since he was a teenager and he lived to be 80!  Smoking can’t be all that bad.”

People often commit Hasty Generalizations because of bias or prejudice.  People also commonly commit Hasty Generalizations because of laziness or sloppiness.  It is very easy to simply leap to a conclusion and much harder to gather an adequate sample and draw a justified conclusion.  Thus, avoiding this fallacy requires minimizing the influence of bias and taking care to select a sample that is large enough.

Another way in which this fallacy is used is by going after “low hanging fruit”, or using a particularly bad example of a subject matter to validate ones argument.  Examples would be using ISIS as an example of Muslims, or using the Westboro Baptist as examples of Christians.

Circular Reasoning/Begging the Question

An argument is circular if its conclusion is among its premises, if it assumes (either explicitly or not) what it is trying to prove.  A good example of this can be found in Tim Keller’s book The Reason for God, where Keller argues for the reliability of the Bible in the following way:

If eventually we put our faith in Jesus, then his view of the Bible will become ours. Speaking personally, I take the whole Bible to be reliable not because I can somehow “prove” it all to be factual. I accept it because I believe in Jesus and that was his view of the Bible.

Keller suggests that we should accept the entire Bible as “reliable” because Jesus viewed the entire Bible as reliable.  And how do we know that Jesus viewed the entire Bible as reliable?  Because the Bible says that Jesus did.  Circular argument.

Such arguments are said to “beg the question”.  This sort of reasoning is fallacious because simply assuming that the conclusion is true (directly or indirectly) in the premises does not constitute evidence for that conclusion.  Obviously, simply assuming a claim is true does not serve as evidence for that claim.  A circular argument fails as a proof because it will only be judged to be sound by those who already accept its conclusion.

Post Hoc (Post hoc ergo propter hoc)

Latin for “It happened after, so it was caused by”, Post Hoc fallacy is committed when it is assumed that because one thing occurred after another, it must have occurred as a result of it.  Example:

Person A:  “I know that prayer works!”                                                                 Person B:  “Based on what evidence?”                                                                       Person A:  “A lady in out church had cancer, and after the congregation prayed over her, she got better.”

There could be a number of other reasons that the lady recovered.  It is also possible that she never had cancer in the first place.  Because prayer proceeded recovery is not sufficient evidence to actually warrant the claim that prayers work.

Post Hoc resembles a Hasty Generalization in that it involves making a leap to an unwarranted conclusion.  Many superstitious beliefs often arise from people committing the Post Hoc fallacy – good luck charms, post-game rituals, prayers, etc.

Post Hoc fallacies are typically committed because people are simply not careful enough when they reason.  Leaping to a causal conclusion is always easier and faster than actually investigating the phenomenon.  However, such leaps tend to land far from the truth of the matter.  Because Post Hoc fallacies are committed by drawing an unjustified causal conclusion, the key to avoiding them is careful investigation.

False Dichotomy (Extruded Middle)

Also known as black & white thinking, the false dichotomy fallacy is committed when a false dilemma is presented, i.e. when someone is asked to choose between two options when there is at least one other option available, or a spectrum of possible choices exists between two extremes.  False dilemmas are usually characterized by “either this or that” language, but can also be characterized by omissions of choices.  Examples:

Claim:  “You are either with God, or against him!”

Claim: “If we don’t teach kids abstinence, they will all become promiscuous!”

Person A:  “I don’t believe in school-sanctioned prayers in public schools.”                                                                                                                           Person B:  “What are you, an atheist?”

Appeal to Ignorance (Ad ignorantom)

Often referred to as “trying to prove a negative”, arguments from ignorance infer that a proposition is true from the fact that it is not known to be false.  Example:

Claim:  “Scientists haven’t been able to prove God doesn’t exist, therefore he must exist.”

Ignorance about something says nothing about its existence or non-existence.

Burden of Proof Reversal

Closely related to ad ignorantom is the burden of proof reversal, where the the burden of proof is placed on the wrong side of the debate.  It is important to note that the burden of proof always lies with the one making the claim.  A popular example, used often in apologetics and movies such as God’s Not Dead is the argument;

“Proof to me that God doesn’t exist!”

The side making the claim is the one charged with providing evidence, not the one calling it into question.

Non Sequitur (Affirming the Consequent)

Non sequitur is a Latin phrase that means “that which does not follow”. It means that the conclusion reached does not follow from the premise(s).   A good example of this:

Person A:  “If the Bible is correct, then we must accept Jesus as our personal savior.”                                                                                                        Person B:  “Jesus is my personal savior!”                                       Conclusion:  The Bible is correct.

Here, the fallacy is that Person A and Person B may in fact be correct, but the conclusion is not a valid conclusion. It does not follow that the Bible must be correct because one person finds that Jesus is their savior, even if to a believer this seems like the case.

A subtle but easy use of the fallacy is related slightly to belief in belief. It could be formed like this:

Claim:  “Religion gives great comfort to people and causes them to do good things.  Millions of people are comforted and are good people.  Therefore God is real.”

The non-sequitur here is a failure to distinguish between what the act of believing can accomplish, and the (almost) completely unrelated question of the truth value of that belief.  Without external evidence to say otherwise, you cannot tell the difference between someone being comforted because God exists, or because they just believe God exists.  In short: the premises say nothing about the existence of God, only that some people believe in it.

Bandwagon Fallacy (Appeal to Popularity)

The basic idea is that a claim is accepted as being true simply because most people are favorably inclined towards the claim. More formally, the fact that most people have favorable emotions associated with the claim is substituted in place of actual evidence for the claim.  A person falls prey to this fallacy if he accepts a claim as being true simply because most other people approve of the claim.

Other variations of this can be Appeal to Belief – the appeal to the fact that most people believe a claim, and Appeal to Common Practice – the appeal to the fact that many people take the action in question.

That about covers it for the Top 10.  Next time we’ll look at a few more of the more popular fallacies that I see used.  Any questions, clarifications, or comments, please leave below.  Thanks for reading.

NOTE:  Most of the descriptions found in this post were taken from other websites, namely the Nizkor Project, and Logical


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