Critical thinking for Students

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The first edition of this book was published as long ago as 1996. At the time, it broke new ground in trying to bring the subject to a wide audience. Fortunately it (and subsequent editions) sold in encouragingly large numbers, justifying my belief that the subject of Critical Thinking should be available beyond the universities.

There are now quite a few textbooks around on Critical Thinking. They come in many versions. Some scream at you in vibrant colour and shout ‘key point’ whenever particular words are used. Some shout less but take you down somewhat unimaginative routes, noting weighty things, but without stopping to see how the subject works in the world around us. Both types fail to show what a wonderfully creative subject this is.

Critical Thinking is an exciting subject because it will change your thinking by showing you all sorts of possibilities, all sorts of ways of looking at things. It will encourage you to ask lots of questions. What does this mean? What more do I need to know? What’s the problem with what that person has said? You don’t need someone to bellow ‘key point’ at you, when you’re asking and answering questions like these. You’ll just experience the fizz of it all when you do.

This book continues in the tradition of its earlier editions. Though it’s been completely rewritten, the promise of the book is the same. If you read this book, you’ll be much more skilful in how you think. Much more. You’ll have thoughts about such things as these, as well as other significant things.

Over to you…

Roy van den Brink-Budgen

It might seem odd to have to start a book on a subject by having to ask the question of what it’s about. In the case of Critical Thinking, however, it’s a question that we need to ask. It’s not that clear what it is about. Just saying the words doesn’t seem to get us very far: ‘critical’ (in what way?); ‘thinking’ (about what?). We can look at various definitions and they still won’t make it particularly clear what’s going on. They won’t tell you quickly what it is, so that you’ll be able to say ‘Ah! I begin to see it now. I can see what it’s about.’ However, once you’ve read the first few pages of this book, you’ll be saying something very close to that.

It’s often said that Critical Thinking is all about the study of arguments. So you’ll find some people (teachers of the subject, and others) fretting right at the start of proceedings about the difference between arguments in Critical Thinking and other sorts of arguments. (I once fretted like them, but have long since seen the light.) Saying that Critical Thinking is all about arguments is something like saying that music is all about a series of notes. It doesn’t capture very much about what’s going on when we do Critical Thinking or why it’s so important. So we’re not even going to look at or ask about arguments at this stage. Walk away from anyone who still insists on focusing on the question ‘What’s the difference between a Critical Thinking argument and other arguments?’ at the beginning, and tell them that you’re off to look at far more significant things.

Critical Thinking is much better seen as the activity of looking at the possible meaning and significance of claims. However, I can see that this also doesn’t convey that much. What’s a ‘claim’?

I use the term in a very simple way. When somebody says ‘such-and-such is the case’ then they’re making a claim. Here are some examples:

Critical Thinking takes claims like these and asks questions about them. This can include the question ‘Is it true?’ but normally Critical Thinking would ask questions like ‘Is this claim telling us something significant?’ and ‘What else do we need to know in order to respond to this claim?’

In a way, claims on their own normally don’t tell us anything beyond the obvious point that’s being claimed. The claim (piece of information, or whatever it is) just sits there. It’s up to us to do something with it. It’s a bit like how a painting just hangs there. It does nothing until someone looks at it and says, ‘That’s good/beautiful/weird/bad/meaningless/expensive…’ So, in a similar way, when you come along and respond to the claim, ‘This is surprising (because) …’, then you’ve started to give the claim significance or meaning. You’ve given it a life beyond the words, if you like.

We’ll now look in some detail at what we can do with a claim. We’ll look at an example.

We said above that Critical Thinking should be seen as the activity of looking at the possible meaning and significance of claims. So what is the possible significance of this claim? Is there any way that we’re looking at anything significant here? At the very least, the claim will probably have surprised you. And the fact that it has surprised you is a big hint that there might be some significance to be found.

Is it telling us anything more significant than the next claim?

The claim that all US presidents have been men is, in an important way, telling us something beyond a simple piece of information. But what it’s telling us will vary from reader to reader. What is its significance? Of course, though we might predict that there will be a female president of the US before 2020, we would probably find it relatively easy to explain why there hasn’t been one so far. (Though there have been other countries which have had a female political leader – Margaret Thatcher is an obvious example – the US is not at all unusual in not having had one.) We could say that this claim is significant because it tells us something about the dominance of men in US politics. The claim shows a pattern that has at least one straightforward meaning.

What about the next claim?

This claim is one that might or might not be significant. On its own, it’s difficult to say. To know if it’s got a significance, we need more information. What else do we need to know? The next two questions are particularly important.

Answers to these questions will help us to answer the next one.

By now, you can hopefully see already that, in looking to see if a claim is significant, we very often need to ask questions about it. These questions might help us to answer the central questions ‘What does this mean?’ and ‘Is this significant?’

Let’s return to our first claim and start to ask questions about it to try to establish any significance.

Here are some questions we could (or perhaps should) ask:

You can see that, to give a claim a significance, to decide what it might mean, we often need to know more about it. By this we mean that we often need to know more about other things that are relevant to it. We’ll look at the first three of these questions to illustrate this.

The proportion is about 10 per cent (the same as in other countries). So, we should expect that, all things being equal, a US President is much less likely to be left-handed than
right-handed.
As a result, the evidence on the very high proportion of left-handers in the last seven presidents takes on a possible significance. One calculation is that there is only a 1 in 1000 chance of there being five out of seven left-handed presidents if all things were equal. (Of course, we have to accept that 1 in 1000 chances do occur, so we have to accept that it might be just an interesting coincidence that so many presidents are
left-handed.
)

Interestingly, no. His Republican opponent was John McCain, also left-handed! If we look further back, the right-handed George W. Bush won the presidential election of 2000 by beating Al Gore in a highly disputed result. The result was very close and, some argue, should have been given the other way. If that had been the case, then Al Gore would have won. And, if he had, that would have been another left-hander on the list!

A further question was this one.

Well, interestingly, only 3 out of the previous 36 were left-handed. This is about what we would expect from our earlier piece of evidence on left-handers making up about 10 per cent of the US population. So what is it about recent presidents that is different?

You can see that, before we can do anything with the piece of evidence on the high proportion of recent US presidents being left-handed, we needed to ask and answer questions about its possible meaning. We’ve done that and we’re probably now considering that the evidence does appear to have a significance.

This would take us in two related directions. One would be to look at possible explanations (why is this the case?). The other would be to look at what
follows
from the evidence and the explanation. (In looking at what follows from a claim, we’re into what are called ‘inferences’.) We’ll be looking at the subject of explanation in detail in the next chapter (when we’ll return to looking at the evidence on left-handed presidents), and at inferences throughout the rest of the book.

Earlier, we said that Critical Thinking should be seen as ‘the activity of looking at the possible meaning and significance of claims’. We then looked at a claim, which was a piece of evidence. We need to return to this point. By claims, you’ll remember, we mean when it is said that ‘such-and-such is the case’. The ‘such-and-such’ that we’re referring to can be not only evidence but also predictions, recommendations, and principles.

We’ll now have a look at some further examples of claims of evidence (or what we’ll call evidence-claims).

Evidence-claims include statistical evidence, scientific evidence, historical evidence, and evidence that ‘so-and-so said something’.

We’ve had a look at some statistical evidence on US presidents. Here are some other statistical evidence-claims:

As with our evidence-claims on US presidents, we would need to ask questions about these claims in order to look at what significance there might be with each of these. (What is the ratio of males to females in other countries? What is the normal life expectancy in the countries that have professional cyclists? What is the normal life expectancy of professional sportspeople?) As you can see, each of the claims will raise further questions about explanation (Why are there so many males compared to females in the UAE?) and also inference (‘So don’t become a professional cyclist if you want a long life.’).

Here’s a claim which is scientific evidence:

In this example, we’re very interested in looking for possible explanations for the evidence. But, as with statistical evidence, we’d also want to ask questions about the significance of the evidence. One question is obviously, ‘How foul does the foul language have to be to work?’ Another one would be, ‘What if someone uses really foul language lots of the time anyway? Would it work for them?’ Questions like this could then be linked to possible explanations to lead towards a possible inference (‘So next time you hit your thumb with a hammer, just shout ****.’).

There are plenty of historical evidence-claims. Here’s an example:

To work out the significance of this evidence-claim, we need to ask the same sort of questions as before. This is because, before we ask any questions, its significance remains locked. Are these figures higher or lower than we would have expected (or are they about right)? Do we need to know more? If so, what do we need to know? How might answers to these questions add anything to the possible significance of this historical evidence-claim?

Do these further related evidence-claims add anything?

The first might be relevant in considering the significance of the number of people executed. The second might be relevant in considering the scale of punishment for crime during the nineteenth century. But, of course, we would need to know much more in order to give a full account of the significance of the first claim on executions and imprisonment.

Historical evidence-claims can be reports of what someone said (or is supposed to have said). Dr Thomas Neill Cream was executed in 1892 for poisoning several people. He was one of those suspected at the time of being Jack the Ripper. His final words in the two seconds just before he was hanged were

So what might that unfinished claim mean? That he was Jack the Ripper? That he knew or helped Jack the Ripper (‘I am Jack the Ripper’s friend/brother/ …’)? Claims can sometimes take us tantalisingly nowhere.

One of the most notorious examples of the disputed significance of a claim are the words, ‘Let him have it, Chris’. These were apparently the words used by a young man named Derek Bentley, already under arrest, to his young friend, Chris Craig, who had a gun. Craig fired his gun and a policeman was shot and died. The big dispute is whether the words meant ‘shoot the policeman’ or ‘let the policeman have the gun’. Unfortunately for the 19-year-old Derek, the jury took it to be the first and he was hanged a few weeks later. The 16-year-old Chris was too young to be executed so is still alive today. You can see a somewhat passionate account of the case at
http:
//
www.bbc.co.uk
/
dna
/
h2g2
/
A9115229
.

Claims that somebody said something are commonly reported in newspapers, on TV, and on the radio. Here’s an example from
The Times
of 3 August 2009.