Critical Thinking

Introduction

Critical Thinking is a really important skill that will serve you throughout your life. It is considered a standard course and an important aspect of the curriculum in most American colleges and universities, yet it is not taught quite so explicitly in the UK.

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This course, reduced from the original AS in Critical Thinking (Unit 1) offered by AQA, and its associated study guide written by Oliver McAdoo, will give you a brief idea of how to apply Critical Thinking in your college courses, particularly if you study courses which involve a lot of evaluation or texts.

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The benefits of studying Critical Thinking include the ability to write better essays and exam answers, as well as analyse and evaluate texts to a much higher degree of accuracy, both now in college, at university in the future, and in the wider world every day. It is therefore an invaluable life skill to learn...

What is Critical Thinking?

In the context of this course, Critical Thinking involves identifying, analysing and interpreting texts.

A text can be anything, from a piece of writing, to a graphic or visual image, to an audio recording or conversation.

You will learn how to:

• identify and interpret what type of text you are looking at and what claims the text is making,
• analyse how and why claims are being justified, and
• evaluate how well the argument in the text has been made, focusing on its strengths and weaknesses.

Take this image, for example. What sort of a text is this? What sort of claims is it making? How and why are those claims being justified? What are the strengths and weakness of the claim, and how well is the argument being made?

Have a think about your answers and then click here.

Reasoned Argument

Critical Thinking generally focuses on the use of ‘arguments’. But what does that mean – what is an argument? Surely it’s not the same as shouting at your parents/siblings/friends when you disagree with them?!

Watch this classic video from Monty Python’s Flying Circus and keep an ear open for the definition of an argument given by Michael Palin’s character:

(If you are unable to view the video, you can read the transcript here)

So, to be a ‘reasoned argument’ a text must have at least one premise (a claim, statement, reason, etc) and a conclusion (or inference) which must be persuasive alongside the previous premise(s).

Let's look at a quick example of reasoned argument being used:

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“Mercedes-Benz is the world’s best car partly because it has the best safety record. In an independent study of 27 foreign and American passenger cars, Mercedes-Benz sedans from 1998-2000 were found to offer better crash protection from head on collisions than the other cars tested (Bundestag Verlung, 2001). These findings corroborate similar results published by consumer watchdog advocate Ralph Nader in Consumer Reports (October, 2002).”

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This is a reasoned argument because you can break it down in the following way:

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Premise 1: "In an independent study of 27 foreign and American passenger cars, Mercedes-Benz sedans from 1998-2000 were found to offer better crash protection from head on collisions than the other cars tested (Bundestag Verlung, 2001)."

Premise 2: "These findings corroborate similar results published by consumer watchdog advocate Ralph Nader in Consumer Reports (October, 2002).”

Conclusion: [therefore] “Mercedes-Benz is the world’s best car partly because it has the best safety record."

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You will see from this that the conclusion does not necessarily have to be at the end of a reasoned argument; it just has to match the other premises being made.

Claims & Assertions

As we have seen, arguments consist of a sequence of claims (the premise(s)) or assertions.

These are usually statements, but these statements can take many different forms, such as:

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Argument Structures

When you are creating a debate or writing an essay, you often need to follow a pattern, or structure, to make sure your argument makes sense. In Critical Thinking, there are two types of argument structure: simple and complex. Using diagrams to help break down an argument is a really good way of seeing how the argument has been pieced together and whether, therefore, it is well reasoned.

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Simple Structure Arguments

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A simple argument follows the pattern of the premises leading directly to the conclusion. This can be nicely expressed in diagram form as below:

Here we can see two types of simple argument - one in which the two premises depend on each other, and one in which the two premises are unrelated statements, but they both reach the same conclusion.

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A T-shaped argument can be:

[P1] Socrates is a man

[P2] All men are mortal

[c] Therefore Socrates is mortal

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whereas a V-shaped argument can be:

[P1] Socrates gets no exercise

[P2] Socrates drinks excessively

[c] Therefore Socrates is unhealthy

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So you can see, in the first instance - the T-shaped argument - the conclusion would not have made sense without both premises, but in the Y-shaped argument, either of the premises could have, by themselves, led to the conclusion.

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Complex Structure Arguments

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But, as I'm sure you are already thinking, this is not how most arguments work in real life - or even in your essays and debates! These tend to follow more complex structures. This is where diagrams can really show you how an argument's structure fits together (or doesn't!). Admittedly, though, they are more difficult to draw...!

Complex arguments involve ‘sub-arguments’ and ‘intermediate conclusions’ which then go on to act as support for the main argument, the conclusion of which is the ultimate point an argument is trying to get us to accept. Let's look at an example which is illustrated in the first diagram above (far left, 'chain of reasoning'):

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TEXT:

‘Most prospective parents would prefer to have sons. Therefore, if the choice is made available, due to advances in technology, it is likely that eventually there will be many more males than females in the population. This would result in serious social problems, so we should prohibit the development of techniques which enable people to choose the sex of their children.’

(AQA Specification)

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Here, the initial premise:

R1) 'Most prospective parents would prefer to have sons.'

only indirectly support the final conclusion. They directly support an intermediate conclusion:

IC) 'If the choice is made available ... it is likely that there will be many more males than females in the population.'

which then goes on to act as support, alongside a further premise:

R2) 'This would result in serious social problems...'

for the main conclusion:

MC) 'So we should prohibit the development of techniques which enable people to choose the sex of their children.'

which is the main point the argument is trying to get us to accept. So you can see, this argument is complex!

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When analysing arguments like this, it can sometimes be better to work backwards - find the conclusion, then see if you can spot the premises which have been used to support it and work out how they all fit together. The reason this is useful is because it helps you to properly confirm that the argument being made is reasoned and not, as we shall see later, a fallacy or assumption...

Assumptions

Assumptions are another type of claim which you will find in some arguments, and they come in two forms: explicit and implicit.

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Explicit Assumptions

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An explicit assumption is a claim put forward which lacks supportive evidence. These claims often function as essential premises in an argument:  

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[P1] Most people in England believe in God.

[C] Therefore we ought to promote the teaching of religion in English schools.

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The ‘reasonable’ assumption here - ‘most people believe in God’ - is explicit and is used to support the conclusion that religion should be taught in schools. But the initial claim is only stated; no evidence or reasons are provided to support it.

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Implicit Assumptions

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The previous conclusion: ‘therefore we ought to promote the teaching of religion in schools’ doesn’t really follow from the initial premise.

The ‘implicit’ (i.e. unstated) assumption that it does follow is even less convincing than the previous explicit one, for this argument would only be valid if we accept the implicit premise that:

[P2] ‘the majority of people believing in something is evidence enough for the promotion of that thing being taught’.

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If a piece of reasoning depends upon an illegitimate assumption (or assumptions), then clearly we have solid grounds for rejecting it.

That doesn’t mean that the conclusion drawn will necessarily be false, nor that legitimate reasons might not be given that would provide acceptable grounds for the conclusion, but rather that untested assumptions do not, in their untested state, provide adequate grounds for accepting a conclusion.

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Let's look at another example:

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Original Argument:

[P] Smoking is bad for your health

[C] Therefore you should quit

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The assumption (or ‘suppressed’ middle premise) from this argument is:

If something is bad for your health, you quit it.

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However, other possible assumptions for this argument might be:

• That smokers value their health more than they value the pleasures of smoking.
• That the desire for good health is greater than the addiction to nicotine.
• That smoking is a rational, rather than a compulsive habit (etc.)!

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Our new argument, were we to take into account all these assumptions, would now be:

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[P1] Smoking is bad for your health.

[P2] If you value your health more than you value the pleasures of smoking and

[P3] Your desire for good health is greater than your addiction to nicotine and

[P4] You see your habit as a rational, rather than compulsive one (etc.)

[C] Then you should quit!

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Do you think these new assumptions have strengthened or weakened the original argument...?

Evaluation / Varying Standards

At A-level, you should be able to assess the quality of an argument objectively, regardless of your own views, and whether or not you agree with its conclusion(s).

A good (strong/effective/persuasive/reliable…) argument is one which offers adequate support for its conclusion. A poor (weak/flawed) argument is one in which the grounds are inadequate.

‘Adequacy’ in this sense is a semi-technical term. It has to do with the balance between the reasons (premises) and conclusion as before; but it is also about the standard of assurance we require from the argument in the first place.

Fallacies / Flawed Reasoning

The term ‘fallacy’ is often used in a loose way to mean any falsehood, for example in: ‘It is a fallacy that garlic is a health-food.’

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Logical fallacies are common errors of reasoning. If an argument commits a logical fallacy, then the reasons that it offers don’t prove the argument’s conclusion. (Of course, that doesn’t necessarily mean that the conclusion is false, just that these particular reasons don’t show that it’s true.) For example: ‘it is a fallacy to claim that garlic is a health food on the strength of low heart-attack incidence in some countries where garlic is eaten.’

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In some cases fallacious reasoning is unintentional on the author’s part. But on occasions it may be a deliberate ploy to ‘win’ a debate, or persuade the audience.

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There are literally dozens of logical fallacies (and dozens of fallacy web-sites out there that explain them). Many have names (some going back centuries), and are often referred to as the Classic Fallacies.  In this short course, we will only look at twelve of the most commonly used ones, but take a look at the links to other sites on the subject for the wider variety.

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	Ad Hominem Unfairly attacking the person making the argument, rather than the issue. Can also mean attacking the character and/or reputation of those that agree with the argument. The Latin means 'at the man/person'.
	Tu Quoque Latin for 'you too', this means justifying one wrong with another. This fallacy involves using other people's faults as an excuse for your own, reasoning that because someone or everyone else does something wrong, it is okay for us to do it.
Please don't do this!! It's just a fallacy!	Cause Correlation and Post Hoc (also known as False Cause) This is when two events are wrongly (or without evidence) linked to each other as cause and effect of the same thing - just because the two events or things are found together does not necessarily mean that they are correlated or linked. Post Hoc particularly refers to a connection made because one event appears to have directly followed another.
	False Dichotomy / False Dilemma Sometimes known as the 'Marmite' fallacy ('love it or hate it?'), this type of fallacy argues that there are only two possible outcomes, when in reality there may be many other outcomes not being taken into consideration.
	Ad Hoc Also known as the 'Questionable Cause' or 'Questionable Explanation', it is sometimes argued that this isn't a fallacy at all. When a claim has been made, and a legitimate objection has been raised to this claim, there may be no other option but to revise the original claim. For example, some people might argue that fishing is harmless fun for all concerned, based on the premise the fish feel no pain. But if convincing evidence was found to prove that fish do in fact feel pain, an ad hoc argument might be that fish don;t feel pain the same way that humans do in order to still argue that fishing is harmless fun.
	Argument from Ignorance This is an argument that takes lack of evidence as grounds for denying something, or lack of contrary evidence as grounds for asserting something. Sometimes, it is not the claim that is fallacious but the reasoning. The classic example of this is "God exists because you can't prove He doesn't!", or conversely, "God doeesn't exist because you can't prove he does!". If you cannot prove something (and neither can the person you are aiming the argument at), then your very conclusion has to be flawed as well.
	Straw Man Misrepresenting or distoring an opposing  viewpoint or argument in such a way that it is easily put down.
	Slippery Slope Sometimes one event can set of a chain of consequences; one thing leads to another, as the saying goes. The slippery slope fallacy is committed by arguments that reason that because the last link in the chain is undesirable, the first link is equally undesirable. NB. This type of argument is not always fallacious. If the first event will necessarily lead to the undesirable chain of consequences, then there is nothing wrong with inferring that we ought to steer clear of it. We need to judge the adequacy of the inital claim to be sure...
	Overgeneralisation / Anecdotal Evidence This argument uses a small number of instances to create a general conclusion. This is clearly a fallacy because the conclusion is based on an insufficient amount of evidence. For example: ‘Manchester is a crime-ridden city. Both times I’ve been there I’ve been mugged.’
Click the above image to see it in full size.	Begging the Question Circular arguments are arguments that assume (in the premises) what they’re trying to prove. If the conclusion of an argument is also one of its reasons, then the argument is circular. The problem with arguments of this kind is that they don’t get you anywhere. If you already believe the reasons offered to persuade you that the conclusion is true, then you already believe that the conclusion is true, so there’s no need to try to convince you. If, on the other hand, you don’t already believe that the conclusion is true, then you won’t believe the reasons given in support of it, so won’t be convinced by the argument. In either case, you’re left believing exactly what you believed before. The argument has accomplished nothing.
	Confusing Necessary and Sufficient Conditions Just because something is necessary for some outcome does not mean it is also sufficient. Necessary conditions are conditions which must be fulfilled in order for an event to come about. It is impossible for an event to occur unless the necessary conditions for it are fulfilled. For example, a necessary condition of you passing your A-level Critical Thinking is that you enrol on the course. Without doing so, there’s no way that you can get the qualification. Sufficient conditions are conditions which, if fulfilled, guarantee that an event will come to pass. It is impossible for an event not to occur if the sufficient conditions for it are fulfilled. For example, a sufficient condition of you passing AS Critical Thinking is that you get enough marks on the two exams. If you do that, there’s no way that you can fail. Some arguments confuse necessary and sufficient conditions. Such arguments fail to prove their conclusions. Example: ‘The engine won’t run unless fuel is getting through. So all you have to do to start it is clean the fuel line.’
	Confusion / Equivocation Sometimes an expression is misused, or used in a purposely confusing or ambiguous way. This is also known as equivocation (or ambiguity), especially when the same word is used with different meaning in the same argument. It may result from ignorance or it may be a deliberate ploy to mislead. Example: ‘The average family has 2.4 children and the Burton family is about as average as you can get. Therefore the Burtons must have either two or three children.’

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You need to be able to recognise each of these fallacies, and also to explain what is wrong with arguments that commit them. Once you’ve learned what the fallacies are, pay attention and see if you can spot any of them being committed on TV, the radio, or in the press. They're particularly popular in politics...

Click here for the full poster  version of this image, or visit: https://yourlogicalfallacyis.com/

Consequences

Thinking through the consequences of an argument allows us to determine whether or not it is acceptable.

Consider the following example…

• The consumption of alcohol is responsible for high crime rates, poverty, death and a general lowering of the quality of life, both physically and psychologically.
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• Therefore, the government has a duty to ban it.

An argument like this was used to defend the American Prohibition (banning of alcohol) act of the 1920s (see the 18th Amendment, 18/12/1917).  At face value, it looks quite convincing, but what would really follow if we were to accept the reasoning it presents us with…? 

First, it would be difficult to see how such an argument could be limited to alcohol use alone.  Any activity, for example gambling or smoking, which had a similarly negative effect should surely also be banned. 

You should be able to see that each of these questions raises doubts about whether the initial argument, as it stands, is acceptable. 

A more sophisticated example comes from a classic defence of freedom of speech. In chapter two of the book On Liberty, the philosopher John Stuart Mill presents us with the following, now famous, piece of reasoning (enshrined in the first amendment to the American constitution):

If all mankind minus one were of one opinion, and only one person were of the contrary opinion, mankind would be no more justified in silencing that one person than he, if he had the power, would be justified in silencing mankind. 

(Mill, On Liberty)

In plain English, Mill argues that there is no situation, except that which would lead to the direct physical harm of another human being, which could justify a restriction on how people express themselves. But just how convincing is this?  Mill attempts to justify his position by considering some of its positive consequences:

• Many beliefs that were suppressed in the past later turned out to be true (for example the church suppressing the belief that the earth was round and not at the centre of the universe).  We have no way of knowing the same won’t hold true of future beliefs, so they should not be suppressed.
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• Allowing for freedom of speech and expression would reduce the persecution of minority groups (for example, those discriminated against or silenced on grounds of gender, race, sexuality or religion).   
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• We have no way of knowing how strong an accepted practice or belief is until we question it. To use a more contemporary example, it was only when the suffragette movement of the early 1900s challenged the view that women were ‘too emotional’ to vote, that this belief was overturned (1928) and women were given equal voting rights to men.)

And each of the above ‘positive’ consequences strengthens Mill’s argument. 
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But the argument doesn’t stop there. Mill believed the suppression of any belief or practice, no matter how repugnant, would damage the general applicability of this law. His reasoning was later echoed in Martin Luther King’s famous claim that ‘injustice anywhere is a threat to justice everywhere’ (Letter from Birmingham Jail). Because of this, Mill argued there could be no circumstance (except the direct causing of physical harm to another individual) under which freedom of speech, thought or expression could be limited.

But this was quite a bold claim!  There are a range of practices that most people would regard as completely unacceptable which would, if we were to accept the consequences of Mill's reasoning, be permissible on the above grounds. For example, people would be free to:
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• take drugs
• be as obscene or offensive as they liked as long as this caused no direct physical harm to another individual
• preach religious fundamentalism
• preach religious, racial or sexual intolerance
• share military secrets
• watch and share pornographic material of an extreme nature as long as they did not produce it.

And each of these possible outcomes, assuming we agree they are unacceptable, would weaken Mill’s position. 

Considering consequences, then, not only allows us to reach a decision about whether or not an argument is acceptable, but also to think about ways in which an argument could be modified in order to make it more so.  The political and social philosopher Joel Feinberg adapted Mill’s ‘harm’ principle to take into account the above points. He argued for an ‘offense principle’ which meant that personal freedoms could be restricted if they are used to cause harm and/or offence (which Mill thought was acceptable) to another individual. 

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If you would like to practice examining and analysing consequences, have a go at the following quiz and check your answers against the suggested answers once you have submitted them.

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Critical Thinking - Consequences Practice (Quiz)

Additional Evidence, Counter-Examples & Analogies

We have seen that thinking through the consequences of a particular argument is an effective method for deciding how strong (or weak) it is, but it is not the only one.  Another way is to consider the impact of:XXX

• additional evidence (material of a factual nature, used to support or develop a reason),
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• counter-examples (used to challenge a general claim or argument), and
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• analogies (appealing to a parallel or similar case in order to shed light on the first)

• Additional evidence can be used to strengthen, weaken, confirm or refute an argument, hypothesis or explanation.
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• Counter-examples function in one of two ways.  Firstly, they can be used to question or refute a general claim or argument and secondly, they can be considered and then responded to in order to strengthen one’s own reasoning.
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• Analogies can be used as an effective shortcut for getting to grips with a difficult idea. A comparison can be drawn between an idea that might be new and fairly complex, and one that should be familiar.
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Additional Evidence

Arguments can be strengthened or weakened by bringing in further evidence of a factual nature. 

Let's take a look at an example:

In Arthur Conan Doyle’s ‘The Adventure of the Norwood Builder’, Sherlock Holmes is dealing with what seems like a pretty cut and dry case. John McFarlane, a young lawyer, is accused of murdering one of his clients – a builder named Jonas Oldacre. He had a motive, was in the area at the time the murder was committed and perhaps most damningly, his stick was found at the scene of the crime. We might summarise this in argument form as follows:

• McFarlane stood to gain a considerable amount of money from Oldacre’s death (R1).
• He was in the area at the time the crime was committed (R2).
• His stick was found at the scene of the crime (evidence).
• Therefore, he is guilty of the murder of Jonas Oldacre (C).

Even Holmes’ is swayed by this reasoning but nevertheless has his doubts.  When a further piece of evidence is discovered:

• McFarlane’s bloody thumbprint (found on a wall in Oldacre’s house).

Lestrade, the police inspector investigating the crime, believes the case to be conclusive. However, Holmes, who had completed a thorough investigation of the house the day before and found no such thumbprint, is able to use this evidence to establish McFarlane’s innocence. He reasons as follows:

• There was no thumbprint on the wall in Oldacre’s house the day prior to its discovery (R1).
• McFarlane was locked up in gaol overnight (R2).
• Whoever placed the thumbprint there could not have been McFarlane (R3).
• So somebody is trying to frame McFarlane for murder (IC/R4).
• And this person, rather than McFarlane, must be the real culprit (MC).

SPOILER ALERT!!

With this additional piece of evidence, Holmes is able to flush out the real culprit (the very much alive Jonas Oldacre who had been running a revenge campaign against McFarlane!) and establish McFarlane’s innocence. 

Additional evidence, then, can be used to strengthen, weaken, confirm or refute an argument, hypothesis or explanation.  In order to test the effect that additional evidence might have on an argument, we need to ask ourselves the question:

‘if the following were true, would it:

a) strengthen/confirm,
b) weaken/refute, or
c) have no effect on the argument in question. 

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Counter-Examples

Counter-examples function in one of two ways. 

Firstly, they can be used to question or refute a general claim or argument and secondly, they can be considered and then responded to in order to strengthen one’s own reasoning. 

A general claim is one that is intended to hold true in every case. They tend to involve reasoning indicators such as ‘all’, ‘every’ or ‘always’, or when phrased negatively, ‘none’, ‘no’ or ‘never’. If such a claim is correct, it will be impossible to find exceptions. This is especially true of general claims that are true by definition, such as ‘all bachelors are male’. Here, a counter-example (i.e. a non-‘male and unmarried’ bachelor) would be impossible. But the majority of general claims do not display this degree of certainty. Because such claims as:

• All swans are white.
• All second-hand car dealers are dishonest.
• All knowledge comes from experience.

are meant to hold true in every case, all that would be required to refute them would be one counter-example – i.e. a non-white swan, an honest second-hand car dealer, and an instance of knowledge that did not come from experience. For this reason, counter-examples often force us to limit the force of our conclusion. The above claims would be better phrased as:

• Most swans are white.
• Some second-hand car dealers are dishonest.
• The majority of knowledge comes from experience.

The harder it is to provide a counter-example for a general claim, the greater the likelihood that it will be true. Conversely, the more counter-examples that can be provided against such a claim, the less plausible the claim will be. Because arguments often depend upon general claims for their effectiveness (although these are often left implicit) looking for counter-examples is an effective method for testing whether or not an inference is sound:

•   The Bugatti Veyron is the fastest (253 mph and 0-60 in under 2.5 seconds) and most expensive (£880,000) production car ever built.
•   It has to be the greatest vehicle on the road.

Here, the reasoning only works if we accept the (assumed) general principles that:

1. An expensive product is always better than an inexpensive one.
2. A faster vehicle will always be better than a slower one.  

And more generally:

3. That in all cases speed and price are what determine how good a car is.

But it is easy to find counter-examples for each of these. 

For the first point, we would just need to bring in an example of an inexpensive product that was superior to an expensive one - for example, buying a pricey new bottle opener that is significantly inferior to the cheaper one already owned.  Price is clearly not always a good indication of quality! 

For the second, we would just need to find an example of a slower vehicle that was superior to a faster one - a Rolls Royce Silver Shadow, widely regarded as one of the greatest cars ever made, has a top speed of 115mph; certainly slower than, but not inferior to the majority of modern, less expensive cars on the market. 

And for the third, we would just need to show that speed and price do not always determine how good a vehicle is. A popular car magazine recently listed fuel consumption, safety, comfort, ease of handling and cost of insurance as being the decisive factors for doing this; none of which the Veyron is likely to score highly on! 

Whilst none of these points fully refutes the inference (or conclusion) drawn, they nevertheless cast doubt upon the reasoning used to arrive at it.

Looking for counter-examples, then, is an essential step for determining how strong an argument is.    

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Analogies

Analogies can be used as an effective shortcut for getting to grips with a difficult idea. 

For example, in the introduction to the AQA Critical Thinking course book, an ‘argument’ was compared to the human body:

• The human body is not just a single unit, but rather, a complex one which can be broken down into many separate parts.  Each of these parts has a function: the heart pumps blood around the body; the eyes provide us with sight and the ears, sound etc. and these individual functions combine to contribute to the body’s functioning as a whole.  An argument is like this, composed of separate parts, each with a specific role. 

Here, a comparison is drawn between an idea that might be new to you and fairly complex (that of ‘argument’) and one that you should all be familiar with (the body).  Because there are suitable similarities between the two things being compared this was a legitimate way of communicating a difficult idea.  Here are some more examples for you to think about:

• The eye is like a camera.
• Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that. (Martin Luther King).
• Religion is the opium of the masses (Karl Marx).
• ‘When they debate as to what the sound of the SLR engine was akin to, the British engineers from McLaren said it sounded like a Spitfire. But the German engineers from Mercedes said "Nein! Nein! Sounds like a Messerschmitt!" They were both wrong. It sounds like the God of Thunder, gargling with nails.  (Jeremy Clarkson, when driving the McLaren Mercedes SLR through a tunnel.)

Analogies are often appealed to in arguments because, if we accept that something holds true in one case, then it should also hold true in parallel cases (i.e. those which are suitably similar). 

Perhaps the most famous example of this type of reasoning was put forward by William Paley who argued for the existence of an ‘intelligent designer’ (God) by drawing an analogy with a watchmaker: 

• In crossing a heath, suppose I pitched my foot against a stone and were asked how the stone came to be there, I might possibly answer that for anything I knew to the contrary it had lain there forever; nor would it, perhaps, be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place. I should hardly think of the answer which I had before given, that for anything I knew the watch might have always been there. Yet why should not this answer serve for the watch as well as for the stone? Why is it not as admissible in the second case as in the first? For this reason, and for no other, namely, that when we come to inspect the watch, we perceive—what we could not discover in the stone—that its several parts are framed and put together for a purpose … [The requisite] mechanism being observed … the inference we think is inevitable, that the watch must have had a maker. Every observation which was made in our first chapter concerning the watch may be repeated with strict propriety concerning the eye, concerning animals, concerning plants, concerning, indeed, all the organized parts of the works of nature. … [T]he eye … would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator. …

(William Paley, ‘Natural Theology’ – adapted from Stanford Encyclopedia of Philosophy)

We could simplify Paley’s argument as follows:

• A watch displays order (all the parts fit together) and purpose (it has a specific function) and for this to be so, it must have been designed (by a watchmaker).
• Analogically, when we look at objects in the world (the eye, animals, plants etc.) we realise that these too display an order and purpose that is too complex to have come about by chance (as with the stone).  They must thus be the product of an intelligent designer (God).

So an analogy is drawn between objects which have been designed for a purpose and the universe. The inference (that the universe too must have a designer) rests upon the assumption that the two cases are suitably alike for the points that hold true of the first to hold true of the second. If we accept this, the analogy works; if we don’t, it doesn’t. 

But what grounds might there be for reaching such a judgement? In deciding whether or not an analogy is effective, three things need to be taken into account. 

First, you will need to be clear about which two things are being compared (in the above example, a mechanism which has been designed, and the universe). 

Secondly, you will need to consider their similarities and differences (whether or not the universe displays a similar sort of design to the watch; whether something manufactured is suitably similar to something natural etc.). 

Thirdly, you will need to judge whether the similarities are significant enough, and that the two cases do not differ in any important aspects, for the analogy to be effective (if the level of design displayed by the watch is significantly different to that displayed by the universe, then the analogy should be rejected). 

This last point is significant because if, as is often the case, there are noteworthy differences, the example will be guilty of committing the weak analogy fallacy:

• Using a condom to prevent the spread of AIDS, is like trying to put out a fire with paraffin (Cardinal Alfonso Lopez Trujillo [paraphrased slightly])

These words were uttered by one of the leaders of the Roman Catholic Church (Panorama, ‘Can Condoms Kill?’). They were preached alongside information contained in a 20 page document which urged that condoms, far from preventing the flow of aids, actually contributed to it. Trujillo argued condoms had tiny microscopic holes in them which allowed the transmission of the HIV virus (this has since been scientifically refuted) and this message was taken to Africa, a Continent ravaged by AIDS. It should be clear that, although visually powerful, the analogy is a weak one. It attempts to convey the message that condoms are responsible for the spreading of AIDS (it was argued that, not only do condoms not work, but they also encourage an irresponsible attitude towards sex) in much the same way that paraffin contributes to the spreading of fire! But the differences between the two cases are so substantial, the analogy fails – although its emotional force blinded many people to this. We might summarise these differences as follows:

• Condoms are used to prevent AIDS whereas paraffin is used to encourage fire.
• The failure rate of condoms is roughly 1.5%; the failure rate of paraffin (to put out a fire) would be 100%.
• Condom use can be regarded as a responsible activity; putting fire out with paraffin, an irresponsible one!

And no doubt there are many others.  In fact, it would be difficult to find any significant similarities between the two cases that could help the analogy. Contrast this example with the following one:

• Using a condom to prevent the spread of aids is like wearing a raincoat to prevent oneself getting wet in a thunderstorm.

Now of course there is at least one important difference here – the threat of contracting AIDS is significantly more dangerous than the threat of getting wet. However, because there are a suitable amount of relevant similarities, i.e.:

• Both offer an effective method for preventing something happening.
• Both offer protection in the form of a barrier from an external threat.

the analogy can be regarded as a fairly strong one. Coming to a decision about whether the relevant similarities between the two things being compared outweigh the differences is the key to evaluating an analogy. The notion of relevance is important here because, whilst it would be fairly safe to argue that:

• your car is a similar make and model to mine and has the same engine, so they probably travel at similar speeds.

because make, model and engine size are all relevant factors for determining a cars speed, it would be exceedingly unsafe to argue that:

• Your car is a similar colour to mine, so they probably travel at similar speeds!

Obviously, the colour of a car has no effect on the speed at which it travels.

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Vagueness & Ambiguity

Whether or not we accept a piece of reasoning will often depend upon how clearly we understand the terms involved. 

 

An expression is vague if its meaning is not fixed or clear. An expression is precise if it is.

 

Example: ‘He is tall’= vague (how tall?) 
               ‘He is 6’5”’ = precise

Some expressions are naturally vague. The example often cited is that of a ‘heap’. Few would argue that two or three grains of sand could be called a heap or that a thousand grains of sand could not. But at what point, during the process of adding grains of sand together, does a ‘heap’ emerge…?

 

Ambiguity

 

A word or expression is ambiguous if it has more than one meaning. 

Typing the word ‘critical’ into the Microsoft Thesaurus, for example, reveals that the word can mean ‘dangerous’, ‘significant’, ‘unfavourable’ or ‘life threatening’! When used within the context of ‘critical thinking’, needless to say, it tends to mean ‘logical’ or ‘analytic’. 

Whenever there is any doubt, we always need to be clear about which meaning of a word is intended and the best guide here is usually context:

 

• The building is in a critical state of repair.
• It is critical you understand this.
• Why do you always have to be so critical? 
• He’s still in a critical condition.

But it is not just words that can be ambiguous, sentences can be too. Here are some examples of genuine headlines taken from local and national newspapers (funwithwords.com) all of which contain ambiguities:

 

It should be clear that each can be read in one of two ways!  Fortunately, it is often the most obvious way that is the correct one.

 

When analysing a piece of reasoning that contains ambiguity, you will need to:

a)  identify the ambiguous term/s involved

b) explain the different ways in which these can be understood and

c)  come to a decision (based on context or additional information) about which of these is the correct one. 

Where no such decision can be made (i.e. when the context of the claim doesn’t fix its meaning) judgement should be suspended.

Reasoning vs. Persuasion

Distinguishing between reasoning and the use of persuasive language

Language serves many purposes.  We use it to ask questions, tell jokes, express value-judgements, give orders, convey and evoke emotions, describe things as being ‘thus and so’ and also to persuade.  We have seen that one way of doing this is to present an argument.  Here, a persuasive inference is drawn and supported by one or more premises which attempt to bring it about.  But this is not the only way.

In the absence of reason, language can also be used to persuade via word-power alone.  Such a process is referred to as rhetoric.  It approximates to convincing somebody that something is the case, without providing reasons for why this is so.

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Classic example:

Winston Churchill’s call to arms: ‘we will fight them on the beaches’ - a rallying cry for the nation to resist Nazi tyranny:

Even though large tracts of Europe and many old and famous States have fallen or may fall into the grip of the Gestapo and all the odious apparatus of Nazi rule, we shall not flag or fail.
We shall go on to the end, we shall fight in France,
we shall fight on the seas and oceans,
we shall fight with growing confidence and growing strength
in the air, we shall defend our Island, whatever the cost may be,
we shall fight on the beaches,
we shall fight on the landing grounds,
we shall fight in the fields and in the streets,
we shall fight in the hills;
we shall never surrender, and even if, which I do not for a moment believe, this Island or a large part of it were subjugated and starving, then our Empire beyond the seas, armed and guarded by the British Fleet, would carry on the struggle, until, in God's good time, the New World, with all its  power and might, steps forth to the rescue and the liberation of the old."

Few would deny the power of such words, nor the persuasive potency of the speech itself, but no argument is being presented. Its persuasive power rests solely upon the emotional language used to express it rather than in the provision of reasons illuminating why we should be so swayed.

Expressions such as ‘fall into the grip of’, ‘odious’, ‘flag or fail’, ‘go on to the end’ etc. are highly charged, rhetorical devices that illuminate just how powerful and persuasive a tool language can be.

Compare: the fact that this type of speech can be used to support ignoble as well as noble causes should remind you just how important the need is for objectivity when analysing such odious examples as the following:

A devil goes through the land, It's the Jew, well-known to us
as a murderer of peoples,
a race defiler, a child's horror in all lands!

Corrupting our youth
stands him in good stead.
He wants all peoples dead.

Stay away from every Jew,
and happiness will come to you!

(Taken from ‘Der Giftpilz’ [The Poisonous Mushroom] a book of fascist propaganda by Julius Streicher – aimed at children)

The ability to discriminate cases where language is used for rhetorical force from those which present a genuine argument is therefore an important one.  Where no reasons are presented, we should not allow ourselves to be seduced by the power of words alone.  Here are two further examples. See if you can identify where language is being used for rhetorical effect:

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1)

2)

We few, we happy few, we band of brothers; For he to-day that sheds his blood with me
Shall be my brother; be he ne'er so vile,
This day shall gentle his condition:
And gentlemen in England now a-bed
Shall think themselves accursed they were not here,
And hold their manhoods cheap whiles any speaks
That fought with us upon Saint Crispin's day.

  (Shakespeare, Henry Vth)

Rhetoric

Rhetoric can be used in a number of less obvious ways than those outlined in the previous section.  It often trades upon the vagueness or ambiguity of a word or expression.  The classic example here is ‘one person’s freedom fighter is another person’s terrorist’. 

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The term ‘freedom fighter’ is positively charged.  A questionable activity is paraded as being morally commendable, even heroic.  However, the term ‘terrorist’ is negatively charged.  It implicitly forces us to consider the actions of such a person as morally reprehensible, regardless of whether this is in fact so. 

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In this respect and depending on wording, such expressions can be said to possess either an emotive content - one that is emotionally charged, or, by contrast, a neutral or cognitive content which captures the expression’s actual meaning.  For example, the term ‘political activist’ might be regarded as a more neutral translation here, insofar as it does not seem to carry the same emotional baggage.

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Alongside expressing neutral ideas in an emotive vocabulary, persuasive language can also be used to couch emotionally negative or positive terms in what look like cognitively neutral ones; a practice known as ‘doublespeak’.  This is done so as to present a negative issue, event or trait in an acceptable light.  Here are some examples:

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‘Friendly fire’: military expression - the accidental shooting or bombing of allied troops.

‘Incontinent ordinance’: military expression – off target bombs.

‘Quantitative easing’: political expression - printing extra money to buy your way out of a recession.

‘Ethnic cleansing’: political expression – racial genocide.

‘The final solution’: political expression – the Nazi holocaust.

‘Downsize/headcount adjustment’: corporate expression – the mass laying off of employees.

Such expressions are used to hide any negative connotations that more literal translations might expose. 

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The use of rhetoric in argument

So far we have looked at ways in which language can be used to persuade in the place of argument.  It is often the case, however, that arguments themselves will employ such language so as to appear more forceful.  Arguments, even sound ones, often fail to convince.  When this occurs, the use of rhetoric can increase their persuasive impact by intensifying the strength of the reasons they bring into play.  When this occurs, we need to consider the effect that such language has on the overall strength of the argument and whether the argument itself would still stand without it.  Identifying and replacing any emotive terms with cognitively neutral ones will allow us to do this:

• Little quivering animals like mice tremble with fear as they enter the laboratory where cruel scientists will perform experiments on them.  The suffering of defenceless little animals horrifies all sane human beings.  Therefore we should punish all such scientist with a taste of their own medicine and burn their wicked laboratories to the ground!             

Here, if we were to exchange the italicized emotive terms with neutral ones, like so:

• Animals clearly suffer in laboratory experiments
• It is wrong for animals to suffer.
• We should ban laboratory experiments on animals

We can see that the original argument loses much of its impact.  This process also reveals more clearly the arguments actual content. 

Presenting Cogent Arguments

Using analysis and evaluation to present cogent arguments

After the extreme wordiness of the last lesson, you’ll be pleased to know this is the last lesson of the unit!

In A level courses, you may at any time be required to respond to questions concerning claims, arguments and issues by presenting your own arguments clearly and concisely. In so doing, you will be expected to:

1. give a clear statement of your conclusion;
2. clearly state the main supporting reasons;
3. where necessary support the main reasons with sub-arguments;
4. introduce examples and evidence (where appropriate);
5. cite general principles in support of your arguments and
6. consider counter-arguments, possible objections, etc., and offer a response to these.

A significant amount of marks are available for doing this in some subjects, so it is a skill well worth honing.

Example:

We shall use a deliberately banal example so that, at this stage, you can focus on the general construction of an argument, rather than dealing with a particular content. Let us then, imagine (sidestepping the obvious absurdity!) that you have been asked to come to a reasoned decision as to whether sandy beaches are preferable to stony ones.  Here there would be three positions that could be argued for (this will be the case for all examples).  Either:

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1. Sandy beaches are preferable to stony ones;
2. Stony beaches are preferable to sandy ones;
3. Both sandy and stony beaches are of equal or similar merit.

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If we were to argue for position 1 (although the same structure applies equally to all three) we might appeal to the following types of reason in support of the inference, remembering that there is no such thing as an exhaustive list of relevant reasons here, nor a definitively ‘correct’ conclusion. What is important rather, is that your reasoning is pertinent and your position convincing:

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1. The superiority in comfort of sandy beaches over stony ones
2. The superiority in attractiveness of sandy beaches over stony ones

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Each of which could be supported by a sub-argument:

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1. You can only hobble over stony beaches, whereas you can run over sandy ones
2. Sandy beaches have a lovely colour that contrasts with the blue of the sea.

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We could also appeal to evidence in support of the main inference (remember, in the exam, you may well be able to extract most, if not all of the evidence you will need from the documents you will be analysing), for example:

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2.  In a recent survey, 72% of those people polled expressed a preference for sand, rather than stone, as a favoured ‘beach-filler’. (!)

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Coupled with relevant examples or analogies:

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3.  Lying on a stony beach is like lying on a bed of nails

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Possible counter-examples should be considered:

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4.  However, some might argue that this fails to account for the tiresomeness of getting sand out of hair and clothing when spending any amount of time on such beaches.

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Which should be responded to:

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5.  Nevertheless, this is surely a price worth paying when contrasted with the pain and embarrassment of having to ‘walk’ down a stony beach in order to get to the sea.

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And finally we draw the inference that:

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• Sandy beaches are indeed preferable to stony ones.

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And the argument is complete.

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Motives, Agendas & Sources

The degree of trust we should invest in a source should directly correlate with its level of credibility:

• Is the source corroborated?  Are there other sources which agree with the one in hand?
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• Does it stem from a reputable (reliable) source?
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• Was this source a witness to the reported events or is the evidence purely anecdotal - i.e. reported second-hand (the difference between a primary and secondary account)?  If they were there, could their ability to see have been hampered in any way by factors that could cloud or otherwise affect their judgement (loss of memory, inebriation, poor eyesight, shock, age etc.)?
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• Does the source have a vested interest to distort the truth (i.e. do they stand to gain anything by doing so)?  Do they have a vested interest to be truthful?
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• Does the source have any relevant expertise (i.e. one that relates to the evidence being presented)?
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• Is the source neutral (i.e. does it present both sides of the argument) or could it be guilty of bias - for example, could the evidence have been interpreted in some way that is less than objective (i.e. one-sided)?  Does it employ any emotive language in order to get its points across?

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C  R  A  V  E  N…

Corroboration;

Reputation;

Ability to observe/judge;

Vested interest;

Expertise and

Neutrality (or lack of it)
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spells out the word craven. 

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Click here for a useful worksheet which you can use if you ever need to analyse a source for it's credibility. 

You could try this out now as an optional activity, or save the worksheet for later use.

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Considering Evidence

 

When considering evidence, you should also note:
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• how credible is it?

• the issue of selectivity – has the author selected a particular piece of evidence to suit their purpose?

• how relevant is it?

• what is the significance of it? What does it show? Does it bring any real bearing on the issue being discussed?

Plausible Explanations

When we come across evidence of an unusual nature, we feel obliged to offer an explanation for our findings - or at least to accept that, when a convincing one is not forthcoming, that one should be provided.

Summary and Review Quiz

Hopefully, from this course, you will now know how to recognise an acceptable, credible and valid argument from one that is flawed or inadequate, as well as how to create your own reasoned arguments.

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Judging Inferences

As long as an inference (i.e. a conclusion):

then it can be regarded as sound.

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This is particularly so if further evidence can be identified which corroborates it. These points apply equally whether you are analysing and evaluating the reasoning of others, or your own.

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Have a go at working through the multiple-choice review quiz, which covers aspects from across this Critical Thinking module, to complete this course.

Critical Thinking Review Quiz

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Other Resources:

Pearson's RED Critical Thinking model

AS Critical Thinking for AQA (by Oliver Macadoo) - on which this course is based.