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3.1 Assessing arguments

Analysing an argument in terms of its claims and premises in itself tells us little. What it does do, however, is make it easier for us to judge or weigh the argument in at least two ways. First, we can examine each premise to decide whether it should be accepted. Second, we can begin to examine the relationship between the premises and the claim. In other words, we can question whether the premises which we are willing to accept make the claim believable or whether the premises could be accepted and the claim still rejected.

This second notion, the relationship between the premises and claim, is called ‘inference’, and we will be looking at it a lot more closely in subsequent posts. Although there are some specific techniques to help us examine inference, seeing it is, in large part, a natural skill of rational creatures, and we all do it unconsciously everyday in many ordinary ways. It is possible without any formal training whatsoever to make a judgment about whether you find a claim believable or not based on premises. What requires practice, and usually some degree of tuition, is the means by which to articulate our response.

To practice assessing an argument, re-read the argument in exercise 3 and your answers, then try exercise 3.1 here. Only after that should you engage with the answer key and notes.

Alternatively, continue reading the book…


1. What is an argument?

Much of the business of philosophy is concerned with arguments – their construction, analysis, defence and refutation – but how do we determine exactly what is and what is not an argument? How do we distinguish arguments from other linguistic and logical functions such as explanations, descriptions, exhortations and the like? How do we assess whether any particular argument is worthy of assent or deserving of dismissal? How do we determine whether an argument’s acceptance amounts to something significant or is merely a nod to the trivial?

The answers to such questions lie in a loose body of techniques and skills called ‘critical thinking.’ They are ‘loose’ in the sense that although there are some very definite and universally accepted techniques involved in assessing the logical validity and soundness of arguments, there is a large dose of creative or imaginative skill involved too. In the 1960s, Edward de Bono coined the term ‘lateral thinking’ to refer to the ability to come up with novel ways of looking at and solving problems. Like other creative arts such as painting, writing, or playing musical instruments, skill at both logical and lateral thinking can be learned.

What is an argument?
In order to answer the questions posed above, it is necessary to first understand what makes a series of sentences an argument, rather than say an explanation, description or other language function. We can determine whether a passage contains an argument by asking whether it contains any claims that are being supported or defended. The sentences that provide – or are intended to provide – the support to a claim are called the premises of the argument. All arguments, by definition, must contain at least one premise and one claim.

Consider the following:

1. Tomorrow’s lecture will be on Kant. It’s the last lecture of the semester, and last year this professor chose Kant as his topic for his final lecture.

The speaker is making an ordinary prediction about what will happen at some future time (in this case, ‘tomorrow’). The prediction, however, takes the form of an argument, which is simply to say that the prediction amounts to a claim with some reason or evidence (a premise) given in support of it. Formally, it can be broken down in this way:

: Tomorrow’s lecture will be on Kant.
Premise: The same professor gave a lecture on Kant at the same point in time in last year’s course.

What links the claim to the premise is an inference. Inference in ordinary language is often signalled by a connecting word after the claim such as ‘because’, or if the premises are stated before the claim, ‘so’ or ‘therefore’:

i. Tomorrow’s lecture will be on Kant because it’s the last lecture of the semester and Dr Burke chose Kant as the topic for his final lecture last year.

ii. It’s the last lecture of the semester, and last year Dr Burke chose Kant as the topic for his final lecture. Therefore, tomorrow’s lecture will be on Kant.

However, when we break down or analyse an argument’s structure, we usually leave the connecting words out. In part, this is because the strength of the inference, its validity, will be something that we want to test when we evaluate the argument, and it helps to reduce the argument to its simplest form in order to do this. We will be discussing inference and validity at length later on.

For now, compare 1 above, with 2 below:

2. I’m really bored. Every week is just the same. Study, study and more study.

Our teenage angst might well be used as a prelude to an argument – a persuasive appeal for a study break or extra allowance might easily follow – but barely stated, it offers nothing to trouble the disinterested parent simply because sentence 2 fails to amount to an argument. The speaker is not here trying to establish or support a claim of being bored. Rather, he is reporting that he is bored and offering an explanation for it.

One way to think of the difference between a claim and other language functions such as reports, descriptions and explanations is to say that a claim must, at least in principle, be capable of being either true or false. The statement ‘I’m really bored’, so long as it is not spoken in jest or insincerity, does not seem capable of being false in quite the same way that the claim in sentence 1 is capable of being false. That is to say, ordinarily, we would not expect a speaker to be mistaken or to turn out to be wrong or ignorant about their own immediate feelings.

The sentence in 3 below also fails to be an argument, but for a different reason:

3. If God exists, then atheism is false.

This kind of sentence is called a closed conditional. It is a statement of the relationship between a finite number of possibilities (in this case, two), where all the possibilities are covered, so the conditional sentence remains logically true no matter what is, as a matter of fact, the case. We say it is closed and remains logically true because even in a world where God were proven not to exist, it would still be true that if God had existed or ever would exist in that world, then atheism would be false. Thus, the sentence 3. is true regardless of whether God exists or not (later, we will learn that 3. is an example of a wider species of statements called ‘tautologies‘).

Open conditionals are ‘if…then’ statements that leave some options out of the statement:

4. If God exists, Jesus was the son of God.

It could be the case that God exists, but still false that Jesus was his son; hence, the conditional is said to be open. Even so, an open conditional barely stated does not amount to an argument if it contains no premise or supporting reason to justify its belief or acceptance. A claim without any premises or supporting reasons for its acceptance is called an assertion and is much like our report of teenage ennui in sentence 2, which is to say it fails to be philosophically interesting.

Conditionals, open or closed, do not on their own make arguments, but they can make claims and premises. Sentence 4 could be a claim if it were backed up with some supporting reason.

Here’s an example of an argument that use conditionals in both its premises:

5. Life on Earth is in peril. If we had not burned so much fossil fuel in the late 20th century, there would not have been so much carbon dioxide in the atmosphere. If there were less carbon dioxide in the atmosphere, the greenhouse effect would not be running out of control.

The form of the argument is:

Claim: Life on Earth is in peril.
Premise 1: If we had not burnt so much fossil fuel in the late 20th century, there would not have been so much carbon dioxide in the atmosphere.
Premise 2: If there were less carbon dioxide in the atmosphere, the greenhouse effect would not be running out of control.

• An argument must contain both a claim and one or more premises
• A claim without any premises is called an assertion

Try Exercise 1 to test your understanding of this post, or continue reading

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