How do you deal with fallacies and other erroneous reasoning? - Chapter 7

Fallacies

Fallacies (fallacys) are arguments that have the same form as the now known arguments, and yet there is something wrong with them. There is an inappropriate connection between the premises and conclusions. Fallacies can fall into two categories: formal fallacies and substantial fallacies . A logical error is made in the first category; the argument is therefore not deductively valid or inductively powerful. In the second category, the connection is based on very general unjustified assumptions or inferences. Various types of fallacies are discussed in more detail below.

Formal fallacies

1. Confirming the consequent of a conditional proposition. This occurs when we argue from the conditional premise that if P (the antecedent), then Q (the consequent) along with the premise that Q concludes that P. For example: If someone is a philosopher then that person is wise. Jan is wise, so Jan is a philosopher.
2. Denying the antecedent of a conditional proposition. This occurs when the conditional premise (if P then Q) together with the negation of the antecedent (not-P) draw the conclusion from the negation of the consistent (not-Q). For example: If someone is a philosopher (P), then that person is wise (Q). Jan is not a philosopher (not-P), so Jan is not a wise man (not-Q).
3. Deriving 'should' from 'being'. This happens when a prescriptive conclusion is derived from only a descriptive premise (s). For example: How can anyone say that the royal family should be abolished? The royal family has long been a central part of Dutch life.
4. The base rate fallacy (see also H4). This occurs when we formulate an argument in the form of: a proportion of a characteristic of one group is higher than the proportion of that characteristic in another group. For example: Rex is either a cat or a rat. 75% of the cats are black, while only 45% of the rats are black. Rex is black, so Rex is probably a cat. This is incorrect, because the number of black rats can still be greater than the number of black cats.

Substantial fallacies

1. The fallacy of the majority. This occurs if we assume that it is true based on the majority believing something. Often this fallacy can be exposed by making the underlying premise explicit and applying it to another case. For example, if you have the following argument: Most highly educated people believe that the government should do more against crime, so the government should do more against crime. The underlying premise is; if most highly educated people think something is like that, it is like that. If you apply this to the argument "Most highly educated people think the earth is flat," you see the argument is wrong. (Though these days there is a surprising number of people that would disagree with you on that)
2. Common practice. This fallacy is roughly the same as the previous one, but this is only a conclusion based on "what most people do".
3. Ad hominem . This fallacy comes in two forms; the first is when someone tries to attack an argument by attacking the person himself and the second is when someone rejects an argument because he does not like or reject the other person. Such as, “I won’t listen to a filthy whore like you.”
4. Ad hominem - circumstance. This is a subtype of the ad hominem trap. It happens when someone puts forward an argument in favour, after which the argument is attacked on the basis that that person would benefit from it (Of course you say that education needs to be improved, because you are a student yourself). However, this would mean that we should never accept an argument that would benefit the person making the argument, which of course is wrong.
5. Tu quoque. This fallacy is also about the connection we make between the suspected lack of credibility and the power of their argument. In Tu quoque , however, it is about inconsistency between the person's advice and his own actions. For instance; “Why should the police not allow me to drive faster than 120 on the highway? They also do it themselves, right? ”However, it is not a valid reasoning to say that an advice that someone gives is not valid if the person does not follow it himself.
6. Claim to authority. This fallacy exists when an argument makes an unjustified claim to authority. This can occur, for example, if the authority in question does not actually have authority for the case in question or if the authority is not sufficiently informed about the case.
7. The perfectionist trap. This occurs when we make excessive demands on an idea or proposal and then reject it because it does not completely solve the problem .
8. Assimilation of morality with legality. This occurs when we assume that everything that is legal is also moral and that everything that is illegal is also immoral. This does not always apply; for example, it is impossible to prohibit everything that is immoral (for example, lying in a relationship). There are also plenty of examples of things that were illegal but not immoral (for example, a ban on voting for women in the past).
9. Weak analogy. Analogies can be interesting and illustrative but are often unsuccessful. There is a trap if the analogy is too weak or if the analogy itself is not a good argument. For example: “It is nonsense to ban firearms. You can also kill someone with a hockey stick, but they aren't banned either, do you? ". This argument is incorrect; that X is similar to Y on a certain aspect does not mean that X and Y are the same in all aspects.
10. Causal fallacies. There are three types of this. The fallacy post hoc ergo propter hoc occurs if we incorrectly deduce that event X causes event Y just because Y occurred after X. The fallacy of confusing correlation with cause occurs if we incorrectly infer that just because X and Y (almost) always occur together (correlation), there is a causal relationship between the two. The reversal of cause and effect occurs if we incorrectly deduce that if XY causes, the absence of XY will occur. For example: If a lack of vitamin E (X) causes accelerated aging (Y), that does not mean that much vitamin E (absence of X) slows aging (occurrence of Y).
11. Epistemic fallacies. There are two types of this. The claim to ignorance occurs when we conclude that 1) something is not true because it is not proven (negative form) or that it is true because it is not proven that it is not true (positive form). The epistemic trap occurs if we incorrectly deduce that if someone believes P, then they should also believe Q because it is about the same thing or person. However, we cannot just assume that someone also knows that it is about the same person and therefore believes both P and Q.

Incorrect argumentation techniques

The following group of arguments are sometimes labelled as fallacies, but are not always invalid or inductive, or even incorrect. However, they are bad argumentation techniques and should be avoided. The different types of false argument techniques are explained below.

Ambiguity

This rhetorical technique arises when we deliberately use a word or words with the intention of confusing the public with the hope that the ambiguity will not be noticed. For example, consider the following argument, which is intended to undermine the idea of ​​universal human rights:

P1) In some countries men have the right to imprison their wives; in some countries men do not have that right.

C1) It is not true that people everywhere have the same rights at all times.

C2) The idea of ​​universal human rights is incorrect.

The ambiguity that is used here relates to the word "rights"; the idea of ​​universal human rights is about universal moral truths, while in P1 it is about what is permitted by law.

Red herring

This technique is about distracting the other from the core of the argument by distracting the person with something irrelevant. This is very similar to the rhetorical smokescreen technique, but an irrelevant premise is given as the reason for accepting the conclusion. Consider the following argument: "The judge should not make the verdict ‘guilty’ in the fraud case against company X. Company X is very popular with its shareholders and moreover makes a lot of profit." That the company is popular and profitable is irrelevant for the judge's judgment when it comes to whether or not the company has committed fraud. However, these types of arguments have a lot of potential to fool and convince the public.

Another common example of the red herring technique occurs if, in response to criticism from another party about its own approach to the problem, the criticism is rejected because it is not itself a solution to the problem.

The ability to recognize the red herring technique often depends on the knowledge you have about the subject in question.

The slippery slope

This technique is used if someone incorrectly assumes that allowing or prohibiting a particular course of action will inevitably lead to further related and undesired events. The rhetorical power of this technique is based on the fear of the unwanted events. An example is: "If cannabis is legalized, this will be the start of a downward spiral of abuse of hard drugs such as heroin." However, no good reasons are given for that downward spiral to actually follow; it only responds to the fear of abuse of hard drugs.

Straw man

This technique exists when someone ignores the actual position of the other and puts down a weaker version of that position through misinterpretation, exaggeration or simplification. This weaker version (the straw man) is then easier to knock down than the real argument.

Bypass the question

This technique exists when the truth of the conclusion is accepted by the premises, and the justice of the premises in turn depends on the truth of the conclusion. Consider the following example: Three thieves rob a bank. The first thief says: "I get the largest share, because I am the leader of our group." The second thief asks: "Who says you are the leader of the group?", To which the first thief answers, "I must be the leader, because I get the majority." This type of reasoning is also called circular reasoning .

False dilemma

This technique is the case when it is pretended that there are fewer alternatives than there actually are. Often someone states that there are only two options while there are actually more. For example, suppose someone asks you if you are in favour of positive discrimination against women in business. You say no, and the other draws the erroneous inference that you are against positive discrimination (while you may also be undecided), or even say that you are sexist.

Too much math

A final point of bad reasoning has to do with the incorrect interpretation of statistical material. One way in which this can occur is to confuse absolute and relative differences . Suppose an advertisement for a new medication states that the risk of a heart attack is reduced by 50% through the use of the medication. What many people do not realize is that this indicates the relative risk. However, this percentage is a percentage of the absolute risk. Suppose the absolute risk of a heart attack is 0.5, taking the medicine would reduce to 58% from 0.5, or 0.25. The effect now suddenly seems a lot less dramatic.

A second way in which incorrect interpretation of statistical material can occur has to do with the margin of error . A margin of error of 3%, for example with a poll before the elections, indicates that the poll predicts the actual percentage within 3% with a 95% chance of correctness. However, many people misinterpret the margin of error, as in the following example: “The poll for the upcoming elections puts party X 3% above party Y (50-47). That is within the margin of error of the poll, so there is actually a draw ”.