Critical Thinking

From: http://get.futurefocusedlearning.net/critical-thinking-cheatsheet

Logical Fallacies

A logical fallacy is defined as an error in reasoning or a false inference within an argument, or an argument that is constructed wrongly. Fallacies fall within these two categories: Informal Fallacies and Formal Fallacies.

Informal Fallacies are errors in reasoning. The conclusion doesn’t follow logically from the premises. Either there is a problem with the premises, such as insufficient, biased, or irrelevant evidence, or a problem with the conclusion, such as there being no logical connection from the premise to the conclusion, or the conclusion goes too far or not far enough, or is irrelevant to the argument. Informal Fallacies may have the proper logical construction, but are fallacious by making an argument where the conclusion is wrong in some manner and doesn’t follow from the premise(s).

A formal fallacy is when the argument is wrongly constructed. Formal fallacies break the rules of logic in the way that they’re constructed. With an argument that’s constructed wrongly, this is a matter not so much of recognizing a fault in reasoning, but a problem in the way the argument is structured.

There are many formal and informal logical fallacies in logic. This is because there is one right or logical way forward and many potential errors which render arguments as fallacious. In a given argument there are many ways to be wrong.

1. Straw Man Fallacy

The Straw Man Fallacy is misrepresenting the position of the opponent. This is done by replacing their position with a different position (a straw man), and then attacking that different position. Changing the opponent’s argument is called a Straw Man because a man made of straw is a weaker version of a man, which is easier to defeat. This fallacy sets up an easy and false version of the opponent’s argument, and then knocks that down or argues against that false position. Meanwhile, the actual argument of the opponent hasn’t been addressed at all. Arguments cannot be conducted under these fallacious conditions because the subject of the argument itself isn’t actually being addressed.

Example: Mary says “This is the best Thai food restaurant in the city.” John responds with “You think this is the best restaurant in the city?”

How to avoid the Straw Man Fallacy:

Make sure that you understand your opponents position clearly. Restate it to the opponent and ask if what you stated is an accurate representation of their argument’s position. This will also prevent against them changing their position later on.

2. Begging the Question (Circular Reasoning) Fallacy

Re-stating or reaffirming the premise (or premises) as the conclusion (without any further explanation or information). Assuming the conclusion in the premises. The problem with this fallacy is that it never progresses the argument past the premise(s). The premises are simply reasserted as the conclusion. Or, the conclusion is put into the premises, and then reasserted as the conclusion. The premise of an argument has to be different in content and meaning than the conclusion. And the conclusion has to be separate in content and meaning than the premise(s), albeit related through logical coherence.

Example: Mary says “John always tells the truth.” Bob asks “How do you know?” Mary responds “Because John says that he always tells the truth.” Of course John’s honesty is what’s in question, and John speaking on his own behalf begs the question. This fallacy is circular because the conclusion is really just the premise restated.

How to avoid Begging the Question:

Make sure that the conclusion isn’t just restating the premise or one of the premises. This means thinking about and comparing the premise and conclusion with each other.

3. Ad Hominem Fallacy

Attacking the person and not their argument. One manifestation of this argument fallacy is saying that the identity of a person disqualifies them from making or engaging in the argument itself. It’s attacking a person, such as their identity or character, instead of attacking their actual position in the argument.

Example 1: Cliff cannot be correct when he says that squares have right angles because he is a bad person and has been known to steal ideas and credit them for himself. The position that squares have right angles or not has been left untouched by this fallacy.

You can see this playing out in the political sphere in modern American politics.

How to avoid the Ad Hominem fallacy:

Make sure that you’re not attacking the person and you’re actually contending with the content of their argument. Leave out any personal biases or irrelevant personal characteristics of the opponent that have nothing to do with the content of the argument. A person can be a bad person in any number of ways and still be logically correct in any given instance.

4. Post Hoc Fallacy “post hoc ergo propter hoc” (after this, therefore because of this) Fallacy

Assuming causality from order of events. Claiming that since B always happens after A, then A must cause B is the fallacy. Order of events doesn’t mean causation, necessarily. Actual causation would remain unexplained by only attending to the sequence or order of events. The sequence of events needs actual causation to be understood in order for causation claims to be made.

Example: Incidents of burglars breaking into cars rises whenever the sun is shining, and declines when it’s raining outside. Therefore, sunny days cause crime.

How to avoid the Post Hoc Fallacy:

The best way to avoid this is to think about whether you actually understand the causal agent or causal story, and that you’re not inferring causing from the order of events. If you realize that you don’t know the cause of the phenomena, it’s best to just suspend judgments until the cause is known.

5. Loaded Question Fallacy

This fallacy occurs whenever a person asks a question which includes their desired outcome, against the position of the person answering the question.

Example: The classic example of a Loaded Question is “Are you still beating your wife?” Whether the person answers yes or no, the person is still framed as a wife beater, whether they are or not.

This is also a tactic often used with lawyers when they’re leading the witness by asking questions to guide the witness to certain conclusions that the lawyer is trying to attain.

How to avoid the Loaded Question fallacy:

This should be easy to avoid since it is usually done intentionally and not by accident.

6. False Dichotomy (False Dilemma, Either/Or) Fallacy

A False Dichotomy is when the arguer is presenting only two possible options or outcomes to a position, when in reality there are more live options.

It’s done to narrow the opponent’s position to only two possible outcomes. It’s an argument tactic designed to lead narrowed and specific options.

Example: Mom tells her child “Do you want to go to sleep now or in 5 minutes?” The false dilemma is that there are more options than now or in 5 minutes, such as going to bed in 10 minutes. Most kids pick up on this tactic used by parents when they’re still in toddlerhood.

How to avoid the False Dilemma fallacy:

Think about whether the options you’re considering do indeed exhaust all of the possibilities, or if there are other legitimate possibilities to consider as well. Think about alternatives before the list of possibilities is narrowed to only two or one.

7. Equivocation (Doublespeak) Fallacy

To Equivocate means to use language in a wrong or misleading way to either conceal a truth or to avoid being committed to a position. The goal behind this fallacy is to mislead the listener through a manipulation of language. Often the meaning of a word is changed mid-argument to serve the purposes of the one who is being misleading. Equivocate is to make an incorrect equivalence between words (or concepts that are at issue within the argument).

Example: An example of equivocating would be to use the word “right” in two ways within an argument: right as in morally correct, and right as in functionally correct (such as the right tool to use for the job).

How to avoid the Equivocation fallacy:

Use your words in consistent ways without shifting meanings.

8. Appeal to Authority (ad verecundiam) Fallacy

Making an appeal to an authority in an argument doesn’t make the argument correct. An appeal to authority can be correct, or incorrect, depending on the substance of the claim that’s at issue. There are experts (authorities) on opposing sides of court cases. They can both be right in certain domains, or within the same domain one can be more correct than the other. Being an expert on a given topic doesn’t mean that anything that the expert claims is therefore correct.

Example: Mary says “The earth is flat.” Bob says “How do you know that?” Mary says “Because my geology teacher told me.” It’s doubtful that a geology teacher would actually teach this, but it illustrates the fallacy.

How to avoid the Appeal to Authority fallacy:

Don’t appeal to any authority as the basis for the legitimacy of your claim.

9. Hasty Generalization Fallacy

Making a claim about something without sufficient or unbiased evidence for the claim. If the evidence did support the claim, then it wouldn’t be called a hasty generalization, it would just be a generalization. The hasty description means that the generalization was done too quickly and without evidence. This is a tricky one because there is no agreed upon threshold of what constitutes a sufficient number of examples or sample size to be considered as legitimate evidence in any given case. Is it more than 50%? However, it can usually be more easily determined as to what constitutes biased or unbiased evidence.

Example: John says “You’re a musician, so therefore you must not have stage fright.”

How to avoid the Hasty Generalization fallacy:

Consider what the evidence is, and how large the sample size is, and whether they’re sufficient to be representative of the whole before making the claim or statement.

10. Appeal to Popular Opinion (ad populum) Fallacy

Making an argument that a position is true or has validity because a great number (or the majority) of people hold to that position. The fallacy here is that the majority may be factually wrong as a result of being misled or having partial information and drawing wrong conclusions.

We’ve seen this in history, in which the majority of people have been misled by their media or by their government or by wrong scientific or philosophical assumptions.

Example: Medieval John says “The sun revolves around the earth, and the earth is fixed in place.” Medieval Mary says “How do you know that the sun revolves around a fixed earth?” To which Medieval John replies “Don’t you know that everyone believes that the earth is fixed in place, around which the sun revolves? It’s common knowledge.”

How to avoid the Appeal to Popular Opinion fallacy:

Consider the merits of the statements on their own grounds without recourse to what others think about it.

From: https://successfulstudent.org/the-art-to-argument-persuasion-logical-fallacies/