Section 4 - Evaluating Arguments Flashcards
What factors must be considered when assessing the use of evidence?
- Precise relevance to reason
- Sufficiency to support claim
- Selective use of evidence
- Averages -> Representative of whole group?
- Alternative explanations
In what way must evidence be relevant to the reason it is supporting?
- Timescale
- Group of people
- Geographic area
Assess the use of evidence:
“In 2005, Detroit police used undercover surveillance and informants to fight organised criminals, and reduced crime by 72%. This shows that the British government doesn’t need to invest more money in police weaponry - guns are not the only way to tackle violent criminals.”
1) Evidence is about Detroit, but it’s used to support a claim about British police -> Not precisely relevant -> British police might have different skills, etc.
2) Evidence is about organised criminals, but it’s used to support a claim about violent criminals -> Not precisely relevant -> Techniques for dealing with organised criminals may not work for violent criminals
What makes evidence relevant?
It has to be about exactly the same thing as the reason.
How does relevance of evidence affect the strength with which the evidence is used?
- Not precisely relevant -> Weakness
* Relevant in any way -> Strenghtens
Why must evidence be sufficient to support a claim?
A reason has to be fully supported by evidence in order to be strong.
Assess this use of evidence:
“We Know Cyprus will be a great place for a holiday - it gets 326 days of sun a year.”
- Insufficient evidence -> Weak
- Lots of sun may be relevant to having a great holiday, but it’s not enough on its own
- We need evidence about other factors
What is selective use of evidence?
When certain information is withheld in supporting a reason.
Assess the use of evidence:
“Many smokers use cigarettes to relieve stress - and with good reason. A scientific analysis of tobacco found that it causes the brain to release hormones that make you feel more relaxed. Stress is bad for your health, so this proves that cigarettes are good for your health.”
- Selective use of evidence
- Evidence about the dangers of smoking, such as cancer, are withheld
- This would prove that smoking is not completely good for your health
Why is selective use of evidence / insufficient evidence a weakness?
- The reason won’t be fully supported
* Strong use of evidence requires all the information needed for us to accept that the reason’s true
What’s the difference between insufficient evidence and selective use of evidence?
- Insufficient -> The evidence provided is not enough to fully support the reason.
- Selective use of evidence -> There is other evidence that could prove the opposite and weaken the reason
How may averages not be representative of a whole group?
- There are different types of average -> Can be manipulated
* Also, averages only give a rough idea of a whole group -> May not be strong enough to offer support for a reason
Assess the use of evidence:
“Kathryn is an excellent instructor. The average time it takes her to teach someone to drive is 67 hours, so there’s no need to budget for more than 80 hours’ worth of lessons.”
- Average is not representative of the whole group
* For some people it may take far longer than 67 hours to drive, so they may need to budget for more than 80 hours
How do you evaluate evidence from a graph or table?
- Just like with normal evidence
* Check that it is relevant, sufficient and representative
Remember to revise assessing evidence from a graph or table.
Pg 43 of revision guide
What is the effect of alternative interpretations of evidence?
If you can offer an alternative explanation for a piece of evidence, it weakens the author’s claim
Assess the use of evidence:
“Newly qualified drivers aged 17-20 are twice as likely to have a crash as more experienced drivers. This shows that the practical driving test is too easy.”
- There are alternative explanations for this evidence
- e.g. Young drivers may be more immature and likely to take risks
- This weakens the use of evidence
What two types of question might you get about evidence?
1) Multiple-choice deciding which piece of evidence most strengthens or weakens an argument
2) Explain one strength or weakness in the use of evidence
When answering questions about strengths or weaknesses in the use of evidence, what is it important to do?
- Don’t just state the strength or weakness.
- Explain how the use of evidence connects to the reasoning.
Bad:
“The evidence is weak because the survey only covers office workers.”
Good:
“The evidence is weak because it only covers office workers and cannot be applied more generally to all work environments such as hospitals or schools, so it doesn’t support the claim that tea needs to be banned in all workplaces.”
Can examples on their own be used to support conclusions?
No, they can make reasons more convincing, but they can’t support the conclusion without the reason.
Why are examples used?
To make reasons more convincing.
What must you do when asked to assess the use of examples in an argument?
- Check to see if the example supports a reason -> On its own, the example is weak
- Check the example is relevant -> Same situation as in the reason + typical of the group
Evaluate the use of examples:
“Our bulldog is wonderful with children - he lets them pull his tail and play with him and is very patient with them. Clearly bulldogs are the perfect family dog.”
- Only example supports the conclusion, no reasons -> Weak
* The example is only about one dog, so there’s not enough reasons to accept a general conclusion about all bulldogs
What things make an example relevant?
- Precisely the same situation as the reason -> Timescale, Area, People
- Typical of the group being discussed -> i.e. Not a exception
Evaluate the use of examples:
“Exercising isn’t a good way to lose weight. When Matt Hegarty was training for a marathon, he was exercising for at least 2 hours a day every day - and he put on weight.”
- Example isn’t relevant.
* The reason is about people wanting to lose weight, but Matt was exercising for a marathon, not to lose weight.
Evaluate the use of examples:
“Horror films often have serious effects on people’s mental health. Last year, a young man attacked and murdered an innocent passer-by just hours after watching Screwdriver II at the cinema.”
- Example is an exception -> Not relevant.
* One man’s extreme actions aren’t representative of the large group of people who watch horror films.
Is it bad is an example illustrates an exception?
Usually yes. But not if they support a claim that states that sometimes something can happen.
Evaluate the use of evidence:
“Doing exercise isn’t always good for you. Runners can damage their joints because it’s a high impact sport, and snow-boarders frequently break bones. So always check with your doctor before starting a new exercise regime.”
- Example is relevant, even though it illustrates an exception.
- Because it supports the claim that sometimes exercise can be bad for you.
When assessing the use of general principles, what factors must you consider?
- Relevance
- Principle that applies in many situations
- Relative strength of opposing principles
In what way must a general principle be relevant?
The principle must be proved to be relevant to the conclusion, usually by other reasons that show it to be true in this situation.
Assess the use of general principles:
“The government shouldn’t allow people to inflict prolonged suffering on animals. Fox-hunting forces a loving creature to run for its life, before being savagely killed. The hunt often takes hours, and causes the fox a lot of suffering. Therefore, banning fox-hunting is the right action to take.”
- The principle about animal suffering is show to be true in the case of fox hunting -> This makes it relevant
- This is strong
How does the number of situations a general principle applies in affect its strength?
The more situations a general principle applies in, the stronger it is.
When might a good principle not give strong support to an argument?
When it is overpowered by a stronger, opposing principle.
What must you do when two principles clash?
Decide which is stronger.
Assess the use of general principles:
“The government shouldn’t allow people to inflict prolonged suffering in animals. Medical research on animals often involves dissection without anaesthetic, and other experiments they subject the animals to a great deal of suffering. Therefore, banning medical research that causes animals suffering is the right action to take.”
- The principle about animal suffering is relevant and applies in many situations.
- BUT its use is weak because it is overpowered by the stronger principle that “we must protect humans from disease and suffering”.
- So its use is weak.
What is strong hypothetical reasoning?
A credible claim that gives a good reason for accepting the conclusion.
What is weak hypothetical reasoning?
An unlikely or unbelievable claim, or one that isn’t relevant to the conclusion.
When assessing the use of hypothetical reasoning, what factors must be considered?
- Is it true that one event will happen as the result of the other?
- Is the condition possible or likely to happen?
- Does the reasoning support the conclusion?
- Does the claim offer some support to the conclusion, but need more information to strengthen that support?
Assess the use of hypothetical reasoning:
“If I explain that I had a date with my boyfriend, then my teacher won’t mind that I haven’t done my homework. Therefore, I won’t do my homework.”
- The condition (“explaining I had a date with my boyfriend”) is very unlikely to lead to the consequence (“my teacher won’t mind”).
- So this hypothetical reasoning can’t support the conclusion.
Assess the use of hypothetical reasoning:
“If aliens invaded tomorrow, then no one would notice I hadn’t done my homework. Therefore, I won’t do my homework.”
- It’s unlikely that aliens will invade -> So the condition is unlikely
- Therefore the hypothetical reasoning can’t support the conclusion
Assess the use of hypothetical reasoning:
“If I’m really nice to my teacher then I might not get in trouble for not doing my homework. Therefore, I don’t need to do my homework.”
- The reasoning is indefinite (“I might not get into trouble”), so it can’t support the definite conclusion (“I don’t need to do it”).
- Therefore this is weak.
Assess the use of hypothetical reasoning:
“If I want to do well at school, then I need to change my homework habits. Therefore, I should start going to Jenny’s house when I have homework to do.”
- The reasoning gives some support to the conclusion.
* BUT the argument needs more information to strengthen it (e.g. “Jenny is hard-working and will be a good influence).
What must you do when asked to evaluate the use of an analogy?
1) Identify what is being compared and what the conclusion is
2) Weigh up similarities and differences
3) Explain how the analogy links to the conclusion and why it’s strong or weak
(If asked for two points of evaluation, make sure each point discusses a different aspect of the analogy)
Do analogies always state their conclusion?
Not always explicitly
What two things are being compared in this analogy:
“Fast food is addictive and can cause significant health problems, such as obesity, which might lead to low self-esteem and other social problems. You may as well give your child a hit of heroin along with their burger, chips and fizzy drink.”
The harmful and addictive effects of fast food are compared to those of heroin.
What conclusion is being drawn from this analogy:
“Fast food is addictive and can cause significant health problems, such as obesity, which might lead to low self-esteem and other social problems. You may as well give your child a hit of heroin along with their burger, chips and fizzy drink.”
You wouldn’t give your child heroin, therefore you shouldn’t give your child fast food.
When evaluating the similarities and differences in an analogy, what must you remember?
Only discuss similarities and differences that are directly relevant to the conclusion.
Analyse the similarities and differences between the situations being compared in the analogy:
“Fast food is addictive and can cause significant health problems, such as obesity, which might lead to low self-esteem and other social problems. You may as well give your child a hit of heroin along with their burger, chips and fizzy drink.”
- Similarity -> Heroin and fast food both cause addiction and health problems, which parents wouldn’t want their children to have.
- Difference -> Heroin is illegal, junk food is not.
- Difference -> Heroin has more health risks, such as contaminated needles, than fast food.
When evaluating the use of analogies, what is it important to remember?
Explain how the similarity/difference links to the conclusion specifically.
When evaluating the use of analogies and asked to make two points of evaluation, what must you do?
Ensure that each point discusses a different aspect of the analogy.
What is the difference between reasons and explanations?
- Reasons try to persuade us of a conclusion that isn’t necessarily accepted true.
- Explanations describe why something is the way it is, to help us understand it better. The final statement is already accepted as true.
How do some arguments use explanations?
To support conclusions.
See pg 49 of revision guide
Break this argument down into parts:
“He got soaked because he forgot to check the weather forecast and didn’t bring an umbrella. If he doesn’t want it to happen again, he needs to be better prepared.”
- “He got soaked” -> Statement accepted as true
- “he forgot to check the weather forecast and didn’t bring an umbrella.” -> Explanation
- “If he doesn’t want it to happen again he needs to be better prepared.” -> Conclusion
When asked to provide an alternative explanation, what must you remember?
- Explanation must be different from those in the text
* Explanation needs a good description of that clearly shows how the cause leads on to the final effect.
What is a flaw?
A mistake in the reasoning used to link an argument’s reasons to its conclusion.
What is the effect of a flaw?
- Flaws weaken an argument
* We can’t accept the conclusion
