Providing and Evaluating Evidence A guide to identifying and handling arguments in written work

Providing and Evaluating Evidence

A guide to identifying and handling arguments in written work

Objectives of this session

• To help understand the nature of arguments, and how argument differs from other forms of prose.

• To identify threads of argument in everyday writing and speech.

• To learn to evaluate evidence put forward in arguments.

Further Objectives

• To think about ways of countering (defeating, undermining) lines of argument. [This is especially useful when trying to anticipate lines of objection to a thesis you are arguing.]

• To consider the two key tasks involved in argument evaluation (looking at the logical form and at the reasons offered)

• To consider how these two tasks shape our approach to our academic work.

What is an Argument?

• In philosophy, the term ‘argument’ is used in a special marked sense.

• An argument is not a heated exchange of opinion. Nor is it one person contradicting another. Rather,

• An argument is reasons in support of a conclusion.

What is an Argument?

• An argument is a set of statements/ propositions supporting another statement/ proposition.

• The statement that is being supported is the conclusion of the argument;

• The statement(s) lending support are called the premise(s).

• In short, an argument is reasons in support of a conclusion

What Statements appear in an argument?

• The types of statements that appear in arguments are variously known as assertions, or propositions.

• A proposition is a statement that may be judged to be true or false.

Exercise 1:Which of the following are propositions?

1. Adelaide is the largest town in South Australia. 2. Blue is a lovely colour!3. Shut the door!4. There is a greatest prime number.5. Can you spare me a minute?6. Murder is wrong.7. I don’t care who is in government – as long as they

improve the city’s transport network.

How do I identify an argument?

• Identifying an argument involves identifying

• what is being argued for (conclusion),

• the reasons offered to support that conclusion (premises).

How do I identify an argument?

In each case, we can identify whether we have a premise or conclusion by asking:

• Are there any indicator words (words that serve the logical function of signalling that a sentence functions as either premise or conclusion)?

• What is this statement doing in this context? (Is it something I am being asked to accept; or something that is used to establish something else?)

Identifying a conclusion• Sometimes a piece of prose will provide indicator words that

tell us a particular statement or claim functions as the conclusion of the argument.

• Conclusion indicator words include:So Therefore ConsequentlyThus Hence We conclude that

It follows that

• Note that the conclusion of an argument need not appear last. Conclusions can appear anywhere in the argument.

Identifying a conclusion• Where there are no logical indicator words to help

identify a conclusion, we can use the context to decide whether we have a conclusion, and therefore an argument.

• We consider the relationship between the statements in the passage, to see whether some of the statements can be taken to support a statement expressing a conclusion.

• Also, we can ask whether the context is argumentative: does this group of sentences without a logical indicator appear in a context in which something is in dispute or controversial?

Identifying a conclusion

Conclusions may• State a supposed fact;• Make a recommendation (using such words as

‘ought’ or ‘should’ or ‘must’). Such words can help identify the conclusion to an argument in some cases.

• Note: If we have a conclusion (claim for which reasons are being offered) then we have an argument. No conclusion means, no argument!

Identifying premises

• These can be identified using logical indicator words, such as

Since because forGiven that as The reasons

are Can be deduced from • In the absence of premise indicator words, we

identify a premise by asking ourselves, is this claim being used to support some other claim?

Distinguishing between arguments and explanations

• Sometimes, the type of indicator words that appear in arguments can appear in sets of statements that are not arguing for something.

• E.g. ‘Since you arrived on the scene my life has been nothing but trouble’.

‘Since’ here signals the passage of time. It is not functioning as a premise indicator.

• Sometimes, indicator words appear in sets of statements that are providing an explanation rather than an argument.

Distinguishing between arguments and explanations

• To decide whether indicator words are being used to indicate an argument or an explanation, consider the status of the claim that is backed by reasons.

• Consider the claim ‘X, therefore Y’. • If this is an argument, then Y (the conclusion) is in dispute.• If Y is assumed to be true by both parties, this is not an

argument but an explanation. We know Y happened and are trying to determine the reasons for it.

See Walton, p.80

Exercise 2:Separating Arguments from non-arguments

• Working in pairs/ small groups and using the worksheet given, try to sort out which examples are discussions/ explanations, and which are arguments.

Conclusion Indicator Words

So Therefore

Consequently Thus

Hence We conclude that

It follows that

Premise Indicator Words

Since because for

Given that as

The reasons are

Can be deduced from

Assumptions

For the purposes of evaluating reasoning, we can define an assumption as

• Something which is taken for granted but not stated;

• Something which is implicit rather than explicit

See Anne Thompson, p.26

Premises in arguments

• Three sorts of premise may appear in an argument:• Basic premises (things explicitly stated, but not

argued for elsewhere in the argument; thus assumed true for the purposes of the argument)

• Non-basic premises (things argued for elsewhere in the argument)

• Implicit premises (things not stated in the argument, that must be assumed if we are to arrive at that conclusion)

Filling in Implicit Premises

e.g.Premise: My husband treated me to an

expensive meal yesterday evening.

[Only men with something to hide tend to treat their wives to expensive meals.]

Conclusion: My husband must have something to hide!

Exercise 3:Identifying hidden premises

• For each of the arguments on the sheet, try to identify at least one hidden/ implied premise that would be needed to get from the premises to the conclusion.

Longer pieces of reasoning

• Not all arguments issue in a single conclusion. Many arguments draw conclusions along the way to the main conclusion.

• These intermediate conclusions may use further premises to help arrive at the main conclusion.

Arguments with Intermediate Conclusions

Consider the following argument:

The birth rate in Western countries is declining very fast. This means that even though people are living longer, eventually the size of the population will fall, and there will be fewer and fewer people of working age to sustain an ageing population. Either it will be necessary to raise the retirement age, or younger people will have to increase their productivity at work.

Arguments with Intermediate Conclusions

Reason: The birth rate in Western countries is declining very fast.

Intermediate Conclusion 1: This means that even though people are living longer, eventually the size of the population will fall.

Intermediate Conclusion 2: There will be fewer and fewer people of working age to sustain an ageing population.

Main Conclusion: Either it will be necessary to raise the retirement age, or younger people will have to increase their productivity at work.

Arguments with Intermediate Conclusions ii

Consider another argument:

The introduction of tests on drivers for drugs such as cannabis is being considered, and it has been suggested that a zero limit may be set. The result would be that someone with even a small amount of cannabis in the bloodstream could be prosecuted. This would be unfair because some people whose driving was not impaired could be prosecuted, since cannabis can remain in the bloodstream for up to four months. So if drug tests are introduced, the limit should not be set at zero.


Reason 1: [If tests on drivers for drugs such as cannabis are introduced] a zero limit may be set.

Intermediate Conclusion 1: Someone with even a small amount of cannabis in the bloodstream could be prosecuted.

Reason 2: Cannabis can remain in the bloodstream for up to four months.

Intermediate Conclusion 2: Some people whose driving was not impaired could be prosecuted.


Intermediate Conclusion 3: This would be unfair

Main Conclusion: So if drug tests are introduced, the limit should not be set at zero.

Exercise 4: Identifying intermediate conclusions in an argument

• Work through the exercise given, trying to identify the main theses being argued for here.

Q: Why does it matter in academic writing whether or not we can identify intermediate

conclusions?

Supporting ConclusionsThere are two ways in which a group of reasons (premises) may support a conclusion:

• The reasons may be presented as jointly supporting the conclusion (taken together they support the conclusion but each in isolation does not)

• The reasons may be independently justifying the conclusion (so that if you accept one of the reasons the author expects you to accept the conclusion)

See Alec Fisher, pp.19-20

Premises jointly supporting a conclusion


Smoking related illnesses don’t really cost the state as much as is often claimed. If no one smoked, the revenue from taxes would be massively reduced, and many smokers will die before collecting their full share of health and retirement benefits.

Premises jointly supporting conclusions

Reason 1: If no one smoked, the revenue from taxes would be massively reduced.

Reason 2: Many smokers will die before collecting their full share of health and retirement benefits.

jointly supportConclusion: Smoking related illnesses don’t really cost the state as much as is often claimed.

Premises independently supporting conclusions


Cigarette advertising should be banned because it encourages young people to start smoking. But even if it had no such influence on young people, it should be banned because it gives existing smokers the mistaken impression that their habit is socially acceptable.

Premises independently supporting conclusions

Reason 1: Cigarette advertising encourages young people to start smoking.Reason 2: [Cigarette advertising gives existing smokers the mistaken impression that their habit is socially acceptable.

Independently supportConclusion: Cigarette advertising should be

banned.

Exercise 5:

Answer the following question, working in groups:

Q: Why would it be useful to known whether an author is providing joint or independent

reasons for their argued position?

Creating Counterarguments

orHow to anticipate objections to your

own thesis

Who to believe?To the extent that [Australia’s asylum] laws were softened – by

allowing most applicants to live in the community, closing the detention centres in Nauru and Manus Island, and abolishing the temporary protection visas that denied rights to refugees who arrived by boat… - there is no clear evidence that this caused an increase in desperate asylum-seekers putting their lives in the hands of people smugglers.

Much of the increase can be explained by global factors, with a recent report by the Office of the UN High Commissioner for Refugees showing a big jump in worldwide asylum applications during the past year….

Who to believe?

And if people smugglers are marketing their services on the back of misrepresenting the changes that Labor made, and if their customers, who are risking everything, are not checking whether the smugglers’ claims of an easy ride are true, it doesn’t necessarily follow that it is the detention policies that need to be changed.

Lenore Taylor, The Weekend Australian, 18-19 April 2009

Who to believe?P1: Asylum seekers are desperate people who will do anything to

escape their circumstances.P2: Asylum seekers are not informed of the finer points of

changes in the refugee policies of potential host countries.P3: In the event that asylum seekers did know the finer point of

these policies, this knowledge would not influence their decision to seek asylum in Australia. [for subargument for this, see next slide]

C: Changes to asylum policy by the current government are not responsible for the recent rise in boat arrivals.

Subargument for premise 3

Pi: The recent rise in numbers of people seeking asylum across the world reflects the changing geo-political situation in a number of countries (e.g. Afghanistan, Iraq, Sri Lanka).

C: The recent rise in boat arrivals has not been caused by changes to the asylum policy brought about by the current government.

Creating a counterargument to argument 1

P1: Asylum seekers are desperate people who will do anything to escape their circumstances.

P2: People smugglers are ruthless individuals who exploit the vulnerability of their clients.

P3: People smugglers are aware of recent changes to Australian refugee policy.

P4: It is people smugglers, and not their clients, who determine the final destinations of asylum seekers.

C: Changes to asylum policy by the current government are responsible for the recent rise in boat arrivals.

Countering the counterargument

P1: Asylum seekers are desperate people who will do anything to escape their circumstances.

P2: People smugglers are ruthless individuals who exploit the vulnerability of their clients.

P3: People smugglers feel no concern for the interests of their clients; and have no interest in ensuring the success of their clients’ asylum applications.

P4: People smugglers do not consider the asylum policies of individual countries when choosing their clients’ destinations.

C: Changes to asylum policy by the current government are not responsible for the recent rise in boat arrivals.

The importance of counterargument

To establish a thesis, it may be necessary to do most or all of the following:

• Provide evidence in support of your preferred conclusion.

• Anticipate lines of objection to your own argument, and arguments/ evidence that will defeat these alternative views.

• Anticipate many consequences of the position you are arguing for.


• The ability to handle counterargument has especial value in dissertation-writing.

• A counterargument often shares certain assumptions with an original argument.

• Being able to formulate different counterarguments allows you to anticipate different directions in which your own argument might be developed by others. It also allows you to pre-empt these alternative lines of argument, or show why you are not committed to them.

Skill in counterargument

• Practice in creating counterarguments allows you to

• identify which of your own commitments you share with your opponents;

• Which commitments you need to surrender/ alter if you are to disagree with opponents.


• Mastery of counterargument helps to identify where you and your opponents share common assumptions; and where your own position diverges from previous academic work on the same topic.In short, it can help you to

1. locate your own work against the work of others; 2. demonstrate how your work makes a unique

intellectual contribution in your discipline/ area.

Further Reading• Alec Fisher, The Logic of Real Arguments, 2nd ed.

(1988; Cambridge University Press, 2004).

• Leo A Groarke and Christopher W.Tindale, Good Reasoning Matters: A Constructive Approach to Critical Thinking, 3rd ed. (Oxford University Press, 2004).

• Anne Thomson, Critical Reasoning a Practical Introduction (London: Routledge, 1996).

Documents

Providing and Evaluating Evidence A guide to identifying and handling arguments in written work