Varieties of Fallacy

 

 

 

What is a Fallacy?

 

There are good arguments and there are bad arguments. In this course we’ve assumed that the ‘goodness’ of an argument – considered as a technique by which people are to be persuaded of some proposition – is captured by the notion of ‘effectiveness. That is, that an argument is good/effective for a respondent if it is such that the argument leads to an increased disposition in the respondent to accept the conclusion of an argument if they accept the premisses of an argument. In the last few lectures we’ve been looking at one very important way in which arguments can be good or effective arguments. We have seen that valid arguments are the ultimately effective arguments. They are as effective or as good as any argument could possibly be because they have the tendency to create an irresistible urge to accept the conclusions given the premisses. (And we’ve also recognised in certain formal properties of arguments ways in which if an argument that is valid is not absolutely convincing as it is presented, it can be altered without changing its meaning to be absolutely convincing.) But we’ve always been aware that there are many other types of effective argument of varying strength. Those arguments that talk about the happy Australian, for example.

 

The ‘happy Australian’ arguments are special case that we’re going to come back to in later lectures. In this lecture we’re going to be looking at some other types of argument that are effective and which are not valid. The arguments we’ll be looking at achieve effectiveness by means of various specific techniques as we’ll see, but they are all marked by a common feature: that they attempt to disguise themselves as valid arguments. In this disguise they arouse our argument intuition in its strongest form, but once we see through their disguise we are in a position to resist the temptations which they present, because we now recognise the types of arguments that they really are – and they are not the sorts of arguments that arouse those argument intuitions. They are – in that respect – illegitimate arguments. These arguments are assigned the pejorative label ‘fallacy’ and they fall into two general categories, formal and informal, the first of which is the least interesting.

 

Formal Fallacies

 

We’ve already had a look at two very common errors in arguments related to the formally valid arguments. We called them formal fallacies because they result from an error in the very form of the argument. But they are fallacies because they are often effective and it can sometimes take some effort to see just why they should not be absolutely effective – ie. valid. And it isn’t until we see that they are invalid that they lose this effectiveness.

 

1.                   Affirming the Consequent

 

                                                                If A then B            +              B

 

 

 

                                                                                                A

 

Example:

 

If you are English then you like fish and chips.

You like fish and chips.

------------------------------

So, you are English.

 

2.                   Denying the Antecedent

 

If A then B            +              Not A

 

 

 

                                                                                        Not B

 

Example:

 

If you are English then you like fish and chips.

You are not English.

------------------------

So, you do not like fish and chips.

 

Informal Fallacies

 

There is no widely accepted categorization of informal fallacies. This is my own attempt at a catalogue raisonné.

 

(Deceit)

 

1.                   Begging the question

 

                Uses the conclusion as one of the reasons to support it.

                Also known as petitio principii or circular argument.

                Note that the offensive reason may be a hidden premiss.

                Such arguments have the form:

               

1              (+            ?)

 

 

…

               

 

  1

 

Note that the form of the argument is actually good. A question-begging argument is formally valid because ‘A, therefore A’ is always going to be true.

 

Examples:

 

i.                     ‘The Bible says God exists. Everything in the Bible is true, because God wrote it. So God exists.’

ii.                    ‘Australia’s present constitution is the best guarantee of stable government because it is the constitution which best protects us from governmental instability.’

iii.                  ‘It’s wrong to murder people. Capital punishment involves murdering people. So capital punishment is wrong.’

 

2.                   Equivocation

 

An ambiguous word is used in two different ways in an argument and the acceptability of the argument depends upon not noticing that difference.

An equivocating argument may appear to be valid, eg. if the argument relies upon an equivocation in the word ‘Q’, then we might see the argument as:

 

                                All P are Q             +              All Q are R

 

 

 

                                                    All P are R

 

But if the equivocation is made clear and Q is replaced by the synonym Q1 for one use and the synonym Q2 for the other use, then the apparent validity disappears because the argument looks like:

 

                                All P are Q1            +              All Q2 are R

 

 

 

                                                    All P are R

 

                Which is no good.

 

Examples:

 

i.                     ‘The laws of nature must have a lawmaker because they are laws, and all laws have a lawmaker.’

ii.                    ‘Nothing is better than eternal heavenly bliss; and a Big Mac™ is better than nothing. Thus a Big Mac™ is better than heaven.’

iii.                  ‘Six is an odd number of legs for a horse. Odd numbers are not divisible by two. Six is not divisible by two’

 

 (Diversion)

 

3.                   Straw Man

 

Argument directed against an inaccurate statement of the opponent’s position

 

Examples:

 

i.                     ‘The theory of evolution states that humans are no different from apes, but humans are clearly smarter than apes, so the theory of evolution is wrong.’

ii.                    ‘People who believe we should spend less on defence apparently believe that the instability in the former Soviet Union and Africa poses no threat to our interests.’

iii.                  ‘I’m in favour of legalised gambling. There are those who oppose it, but they apparently believe that anything that’s fun is sinful.’

 

4.                   Slippery Slope fallacy

 

An argument against a proposed action which claims that it will very probably lead to bad consequences is a s. s. fallacy if the claim of high probability is not supported. (If the claim is supported then it is not a s. s. fallacy but a good s. s. argument.)

 

Examples:

 

i.                     ‘Legalised voluntary euthanasia sounds fine, but inevitably the conditions for euthanasia will be loosened. First, incurable terminal diseases will be included, then merely debilitating conditions, then expensive-to-treat illnesses, then simply inconvenient illnesses will qualify.’

ii.                    ‘First they’ll ask for guns to be registered, then they’ll want to institute a licence test, then they’ll ban certain weapons, then they’ll take them all away, and we’ll be quite defenceless.’

iii.                  ‘It’d be a mistake to try to recreate the welfare programs of the 60s and 70s. If you give people something, they’ll come to expect it, and then to regard it as a right. Who would then work rather than sit back and be paid.’

 

5.                   False Dilemma

 

One of the reasons supporting the conclusion is a false (or inadequately argued) division of possibilities into a dichotomy. Such arguments have the form:

 

                                A or B                    +              not A

 

 

 

                                                                B

 

Notice that this is a valid argument. What makes it a fallacy is the falsehood of the choice that is taken as a premiss.

 

Examples:

 

i.                     ‘Don’t vote for the bill requiring a deposit on bottles. There’s lots of litter other than bottles; we should require a deposit on all potential litter or on none.’

ii.                    ‘You’re either part of the solution, or part of the problem.’

iii.                  ‘Either we ban all guns or we let crime run amok.’

 

 (Irrelevance)

 

6.                   Argumentum ad hominem

 

A personal attack is made on someone, and that attack is taken to be a reason for rejecting the argument that they are putting forward. Generally, such arguments, where they are not purely abusive (and are thus perhaps poisoning the well or ad baculum) are attempting to undermine the assumption that the person being attacked is participating in the argument in good faith. In such uses there may be a suppressed argument roughly like:

 

1(Attack on A)

                                       a

 

[A is not trustworthy]         +  2[believe someone iff they are trustworthy]

 

 

 

A says that X       +              [don’t believe what A says]

 

 

 

Don’t believe that X

 

There are legitimate as well as illegitimate (fallacious) ad hominem arguments. What distinguishes the two is typically the strength of the inference (a), and the truth of (1), and also whether the hidden premiss (2) is reasonable in the context of the argument.

 

 

Examples:

 

i.                     Abusive: ‘We have to act now to save the forests.’

‘You would think that, you’re a hippy.’

ii.                    Circumstantial: ‘We should develop normal relations with Cuba.’‘You only say that because you want to make money selling their fancy cigars.’

iii.                  Tu quoque: ‘You’re telling me I should drink less? You haven’t been sober in a year!’

 

7.                   Genetic fallacy

 

Closely related to the ad hominem argument.

There are always reasons why someone holds the beliefs they do. These reasons are to be distinguished from the justifications which they might offer for holding these beliefs. (Eg. A Catholic may believe in God because he was brought up that way, but he may justify his belief in God by revelation or philosophical argument.) A genetic fallacy is committed if one attacks the causes of a belief rather than the justifications for it.

 

Examples:

 

i.                     ‘Studies show that passive smoking is quite harmless.’

‘Those studies were all commissioned and funded by cigarette companies.’

ii.                    ‘The best system of insurance includes a type of no-fault policy.’

‘That’s a type of insurance policy being promoted by the insurance companies themselves. I’m sure it can’t be good for their customers.’

iii.                  ‘Psychiatric hospitals arose from an attempt to control disruptive elements, not to help them. We should eliminate them.’

 

8.                   Authority

 

Appealing for support to someone whose authority (if any) is not relevant to the matter in question. Notice the similarity in the suppressed argument that seems to lie behind this fallacy to that which lies behind the fallacy of argumentum ad hominem:

 

1(A is an authority)

                                                                 a

 

[A is trustworthy]                   +  2[believe someone iff they are trustworthy]

 

 

 

A says that X       +              [believe what A says]

 

 

 

Believe that X

 

There are legitimate as well as illegitimate (fallacious) arguments from authority. What distinguishes the two is typically the strength of the inference (a), and the truth of (1), and also whether the hidden premiss (2) is reasonable in the context of the argument.

 

Examples:

 

i.                     ‘Can you doubt that air has weight when you have the clear testimony of Aristotle affirming that all the elements have weight including air, and excepting only fire.’

ii.                    ‘I’m not a doctor but I play one on TV.’

iii.                  ‘A majority of doctors think that the morality of young people has declined.’

 

9.                   Ignorance (Argumentum ad ignorantiam)

 

Claiming that something is true because it has not been proved to be false, or false because it has not been proved to be true.

Such arguments rely upon a hidden premiss and have the forms:

 

‘A’ is not proved                 +              [If ‘A’ was true it would have been proved]

               

 

 

     ‘A’ is not true

 

‘not A’ is not proved          +   [If ‘A’ was false, ‘not A’ would have been proved]

               

 

 

        ‘A’ is true

 

These are fallacies when the hidden premiss is obviously false, or if it is not obviously true and yet is not argued for.

 

Examples:

 

i.                     ‘My wife must be having an affair since I can’t prove that she isn’t.’

ii.                    ‘Since no one has been able to prove God’s existence, God does not exist.’

iii.                  ‘Since no WMD’s have been found, there were never any WMDs.’

 

10.                Motivational Appeals

 

Attempting to induce someone to accept a conclusion by appealing to motives rather than providing reasons to think that the conclusion is true.

 

Examples:

 

i.                     Force (Threat, Fear, Argumentum ad baculum): ‘You should not put smoking bans in your restaurants because if you do we smokers will boycott you, and we are a large part of your customer base.’

ii.                    Pity (Argumentum ad misericordiam): ‘I am qualified for this job – I have some expeience and I need the money to get my baby sister into the eye-hospital.’

iii.                  Prejudicial (Poisoning the well): ‘Would anyone be so naďve as to doubt that the finest painters were French?’

 

 (Miscellaneous)

 

11.                Sorites

 

Claiming that two alternatives cannot be uncontroversially distinguished, and that therefore there is no difference between them.

The argument appears to rely upon a hidden premiss that if two concepts are different that there is a sharp division between them.

 

               


Property P1 is defined in terms of X.

                Property P2 is defined in terms of X.

                X can vary by small increments.

A has property P1.

[For anything, B, with property P1, if property P1 is different from property P2 then there is a point at which incremental variation of X from that which defines P1 towards that which defines P2 is sufficient to result in B having property P2 rather than P1.]

If A has P1 and X is incrementally varied then A still has property P1.

Therefore, there is no point at which incremental variation of X from that which defines P1 towards that which defines P2 is sufficient to result in B having property P2 rather than P1.

Therefore, P1 and P2 are not different.

 

(That’s looks pretty hairy itself. It makes more sense if you substitute:

  P1 = ‘hairy’, P2 = ‘bald’, X = ‘number of hairs’, A = ‘Bob’) 

 

Arguments like this are fallacious if the hidden premiss is not true (because the concept is genuinely vague), or if it is not obviously true and yet is not argued for.

 

Examples:

 

i.                     From the moment of conception, a foetus grows and changes constantly. At each moment it differs in only the slightest way from the previous moment. What, then, is the exact point at which the foetus ceases to be a mere foetus and becomes instead a person? For any point identified as the moment when a foetus becomes a person, the foetus at that point will not differ significantly from the foetus a moment earlier. Since we can’t identify any moment at which a foetus becomes a person, and yet the child is already a person when born, the foetus must be a person from the moment of conception.

ii.                    All animals have rights and we ought to respect these rights. How so? Humans have rights, we all accept that. But what is the relevant difference between humans and higher apes? – say the chimpanzee? Humans and higher apes are both conscious, intelligent beings, capable of learning and communicating through language. Apes, in turn, are closely related to other higher mammals, higher mammals to lower mammals, and lower mammals to other animals. Exactly where do rights come into the picture? We cannot draw a sharp and non-arbitrary distinction between those animals whose rights we ought to acknowledge and those we needn’t bother with, so the rights of all animals ought to be respcted.

iii.                  (Robert Nozick (1974), Anarchy, State, and Utopia, New York: Basic Books, pp 290-292)

1.             There is a slave completely at the mercy of his brutal master’s whims. He is often cruelly beaten, called out in the middle of the night, and so on.

2.                    The master is kindlier and beats the slave only for stated infractions of his rules (not fulfilling the work quota, and so on). He gives the slave some free time.

3.                    The master has a group of slaves, and he decides how things are to be allocated among them on nice grounds, taking into account their needs, merit, and so on.

4.                    The master allows his slaves four days on their own and requires them to work only three days a week on his land. The rest of the time is their own.

5.                    The master allowes his slaves to go off and work in the city (or anywhere they wish) for wages. He requires only that they send back to him three-sevenths of their wages. He also retains the power to recall them to the plantation if some emergency threatens his land; and to raise or lower the three-sevenths amount required to be turned over to him. He further retains the right to restrict the slaves from participating in certain dangerous activities that threaten his financial return, for example, mountain climbing, cigarette smoking.

6.                    The master allows all of his 10,000 slaves, except you, to vote, and the joint decision is made by all of them. There is open discussion, and so forth, among them, and they have the power to determine to what uses to put whatever percentage of your (and their) earnings they decide to take; what activities legitimately may be forbidden to you, and so on.

7.                    Though still not having the vote, you are at liberty (and are given the right) to enter into the discussions of the 10,000, to try to persuade them to adopt various policies and to treat you and themselves in a certain way. They then go off to vote to decide upon policies covering the vast range of their powers.

8.                    In appreciation of your useful contributions to discussion, the 10,000 allow you to vote if they are deadlocked; they commit themselves to this procedure. After the discussion you mark your vote on a slip of paper, and they go off and vote. In the eventuality that they divide evenly on some issue, 5,000 for and 5,000 against, they look at your ballot and count it in. This has never yet happened; they have never yet had occasion to open your ballot. (A single master also might commit himself to letting his slave decide any issue concerning him about which he, the master, was absolutely indifferent.)

9.                    They throw your vote in with theirs. If they are exactly tied your vote carries the issue. Otherwise it makes no difference to the electoral outcome.

The question is: which transition from case 1 to case 9 made it no longer the tale of a slave?

 

12.                False Analogy

 

Arguing faultily that because two things have certain similarities they will also have other similarities.

 

An argument from analogy generally looks like this:

 

1.                    It is claimed that the Object (an argument, or a natural phenomenon, or an idea, or what you will) has properties P1, P2, …, Pn.

2.                    The Analogue also has properties P1, P2, …, Pn.

3.                    The analogue has property P.

4.                    Therefore the object has property P.

 

The argument relies upon the hidden premiss that

 

[5.            If two objects share properties P1, P2, …, Pn, they will also share property P.]

 

Arguments like this are fallacious if the hidden premiss is not true or if it is not obviously true and yet is not argued for.

 

Examples:

 

i.                     A country is like a ship with the president as the captain. Just as the captain should be obeyed without question during a storm, the president should be given special powers in periods of crisis.

ii.                    The finances of a government are like the finances of a family. A family can’t go on spending more than it earns.

iii.                  Spending a great deal of money to provide medical care for the aged is like wasting money on a car. When a car is all worn out, needs a new engine, transmission, and body work, it’s better just to junk it. The same goes for people.