Thinking Skills: Critical Thinking and Problem Solving

16 Unit 2 Critical thinking: the basics

A claim or assertion is an expression that is

supposedly true. It may be spoken or written,

or sometimes just thought.

We have to say ‘supposedly true’ because

obviously not all claims and assertions are true.

Some are deliberate lies; some are based on

mistaken belief. There are also some claims

which, as we shall see, are not straightforwardly

true or false, but can still be asserted, or denied.

(A denial is a kind of assertion, an assertion that

something is not so.)

Here are three illustrative examples:

[A] Angola shares a border with Namibia.

[B] The dinosaurs were cold-blooded.

[C] Top bankers earn too much money.

All three sentences are statements. ‘Statement’

here is used in the grammatical sense to

distinguish between sentences that usually

express claims and those which are used to

ask questions or give commands. If you want

a more formal grammatical term, the three

sentences are all declaratives (or declarative

sentences), as opposed to interrogatives

(questions) or imperatives (commands).

It is important to keep in mind the

distinction between an actual sentence – a

string of words – and what is expressed by a

sentence: the claim. A claim can usually be

made in many different ways. For example, [A]

could just as well have been expressed by the

sentence:

[A 1 ] Angola and Namibia are

immediate neighbours.

The wording is different but the claim is

practically the same. Arguably the same claim

2.1

Unit 2 Critical thinking: the basics

Claims, assertions,

statements

or assertion could also be made by sketching

and labelling a map showing the two

countries next to one another.

Since [A], [B] and [C] are all claims, all three

can be judged to be true or false. You may not

know whether a particular claim is true, but at

least it makes sense to say that it is; or that you

agree or disagree with it. It makes no sense to

say that a question or command is true.

Fact and opinion

Claims can be divided roughly into those that

state facts and those that express opinions.

This is a useful distinction, but it needs some

clarification.

Activity

Look again at the three expressions above,

[A], [B] and [C]. They are all grammatical

statements. They all express claims. Discuss

how, if at all, they differ from each other.

Commentary

A fact is a true statement. Of the three

examples, the first, [A], is a fact. What is more,