Key points
- A strong argument is supported and balanced. It offers logical support for its conclusion.
- A weak argument has gaps or bad connections between the premises, undermining their link to the conclusion.
- When constructing or analysing an argument, examine any errors or weaknesses in logic related to the claim or conclusion.
How to construct an argument
Constructing an argument is essential to essay writing. An argument is a particular stand on an issue or question. It is made up of a series of claims. There are 2 types of claims.
- Thesis statement: the main or final claim you are trying to prove – often the answer to a direct question. It is the logical conclusion of all the claims you make in your writing.
- Premises: other claims that contribute to or support the thesis statement – often topic sentences of paragraphs.
To support each premise, you must provide the sources, facts and discussion.
If you're asked to argue a concept, you are being asked to provide evidence to support your premises, which in turn support your conclusion.
The thesis statement will appear in the introduction and conclusion of an essay. Each premise or claim is usually in a separate paragraph, supported by its evidence.
Identifying a claim in a source
You can often identify a premise or a conclusion by the kinds of words used.
- Premise: since, because, as, for, given that, assuming that
- Conclusion: thus, therefore, hence, so, it follows that, we may conclude that
Source: The art of questioning: An introduction to critical thinking (Massey Library login required)
Sometimes, the same claim can be used as either a conclusion or a premise, depending on the point you want to make:
"Your car is dirty [conclusion] because you drove through some mud [premise]."
"You should wash your car [conclusion] since your car is dirty [premise]."
Source: Smart thinking: Skills for critical understanding and writing (2nd ed.), Page 19 (Massey Library login required)
Making a strong argument
A strong argument offers logical support for its conclusion.
A strong argument is:
- Supported: the evidence is convincing and objective, and it supports the claims
- Balanced: the argument considers all the different perspectives and comes to a reasonable conclusion based on those perspectives
- Coherent: the argument 'hangs together'. An argument is weak if there are gaps or bad connections between the premises which undermine their link to the conclusion
- Logical: the argument is clearly and consistently reasoned. An argument that contains errors of logic (also known as logical fallacies) is weak
Examine the strength of your argument by applying the principles of critical reading.
Logical fallacies
When constructing or analysing an argument, check for any errors in logic related to the claims.
Logic errors will weaken your argument and you may receive lower marks.
Source of the information
Three logical fallacies related to this are ad hominem, argumentum ad populum and argument by authority:”
Ad hominem
This is a weak argument that involves attacking the person making the claim instead of addressing the claim itself.
Example
Johnson (2006) does not have a PhD in nuclear physics, so his argument must be incorrect.
Argumentum ad populum
This weak argument suggests that an idea is correct because many people believe it is true or because it has been popular or traditional.
Example
Slavery has always been legal, so it must be moral.
Argument by authority
This weak argument uses the authority of the source as proof of the validity of the argument.
Example
O'Neill (2006) has been a film critic for 40 years and calls Jaws the greatest film ever made, so Jaws is the greatest film ever made.
Connection between claim and evidence
Correlation versus causation
An argument error about correlation suggests that 2 events are related or one is caused by the other, because they happen at the same time or one after the other.
Example
Crime increased following the Rainbow Warrior bombing, so the bombing must have caused an increase in crime.
Overgeneralisation or oversimplification
This type of argument assumes too much or too little based on the evidence.
Example
The weather forecast said it would rain today, and it did, so the weather forecast is always correct.
Appeal to ignorance
An appeal to ignorance uses a lack of evidence as proof for the opposite position.
Example
No one saw Amelia Earhart die, so she must still be alive.
Consideration of other evidence
Confirmation bias
This is focusing on evidence that supports the argument while ignoring evidence that disagrees.
Example
The results from experiments 1 and 2 show that the mean is the same as that predicted, which confirms the hypothesis; experiments 3 and 4 produced data not consistent with this, so they should be disregarded.
False dichotomy
This considers only the extremes of the argument and ignores other alternatives, such as a more reasonable approach in the middle.
Example
In order to be successful in business, you either have to focus on either customer or employee satisfaction.
Straw man
This involves misrepresenting a counter-argument and then arguing against that weaker form instead of paying attention to the strongest counter-argument.
Example
Taxes should be raised. Those who want taxes kept low want unemployed people to starve.
Half-truths
This misrepresentation error means providing a statement that has some truth, but that doesn’t tell the whole story. This can lead to false conclusions.
Example
Fat is bad for you, so you shouldn't eat any fat.
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