Strengthen/Weaken Questions
Argument types
There are three main argument types:
- causal arguments: A->B (read as A causes B)
- analogous arguments: A = B (read as A equals B)
- statistical arguments
Causal arguments are simply cause and effect relationships.
For example,
Every time I brush my teeth, people smile at me. Therefore, it is the fact that I brush my teeth that people smile at me.
The conclusion that people smile at me relies on the assumption that there is no other possible cause that people smile at me other than I brush my teeth.
Here is a shorthand notation:
I brush my teeth->people smile at me
Whenever you see an argument like this ask yourself if there might be a alternate cause.
An analogous argument compares one situation to another.
For example,
Cell phone radiation causes cancer in mice. Therefore, you should not use cell phones.
The conclusion that you should not use cell phones is based on the premise that cell phone radiation causes cancer in mice. The author suggests that mice are the same as humans.
Here is a shorthand notation:
Mice = Humans
Whenever you see a comparison in critical reasoning you must take care that the situations are comparable.
Statistical arguments use statistics as proof.
For example,
Four out of five doctors prefer the cold medicine. You should try the cold medicine.
The conclusion that you should try the cold medicine relies on the statistics that four out of five doctors prefer the cold medicine. Whenever you see statistical arguments, you should make sure the statistics are representative of the group.
Strengthening the Argument
If you are told to strengthen an argument, you’re probably looking at closing a gap in the argument’s logic. Here are the steps:
1)Read the argument.
2)Find the conclusion. Look through the answer choices and see which choices make the conclusion stronger.
3)Decide on the type of the argument: causal, analogous, or statistical
4)Anticipate the answer in your own words.
5)Choose the best answer. Look for an answer choice that will add information to the argument. Scope shouldn’t be a concern on strengthening questions. Answer choices that are found in the original argument are wrong.
Strengthening Question Stems
Which of the following,if true, most strengthens the author’s argument?
Which of the following,if true, most strongly supports the author’s hypothesis?
Strengthening Argument Types
causal argument (A->B) :We must show that the first event A does indeed cause B.
analogous argument (A=B) : We must show the the two groups A and B are the same.
statistical argument : We must show that the statistics are representative of the whole group.
An example
Most road repairs require more resources than is budgeted, but last summer’s nighttime repairs of the highway required no more resources than had been budgeted. Therefore, making summer repairs to roads at night save resources.
Which of the following most strongly supports the conclusion drawn above?
a) The smaller number of cars on the roads at night and more comfortable temperatures allow workers to work more efficiently.
b) Road repair crews that work at night mark their work sites with flashing lights in addition to the orange ones they use during the daytime.
c) The budget for repairs to the highway was generous enough to make it unlikely that it would be exceeded.
d) Road workers who are willing to work at night have an easier time finding jobs.
e) Asphalt used in road repair tends to expand in warmer temperatures and contract in cooler temperatures.
The correct answer is A.(Highlight to reveal)
Let’s why.
Steps:
1)Read Argument
2)The conclusion is: Making summer repairs to roads at night saves resources.
3)The argument is causal: Working at Night -> Saved Resources
4) We have to show that working at night saves resources.
5) Only choice A) strengthens the conclusion. Choice A) introduces new information that at night there are smaller number of cars and it’s cooler outside. This allows workers to work more efficiently. We have shown that working at night does indeed save resources.
Weakening the Argument
Weakening the question requires you to expose a hole in an argument.
Here are the steps:
1)Read the argument.
2)Find the conclusion. Look through the answer choices and see which choices make the conclusion weaker.
3)Decide on the type of the argument: causal, analogous, or statistical
4)Anticipate the answer in your own words.
5)Choose the best answer.
Weakening Question Stems
Which of the following,if true, most weakens the author’s argument?
Which of the following,if true, most weakens the author’s hypothesis?
Weakening Argument Types
causal argument (A->B) :We must provide another possible cause for B.
analogous argument (A=B) : We must show the the two groups A and B are different.
statistical argument : We must show that the statistics are not representative of the whole group.
An example
In a recent study, sedentary middle-aged men who drink more than two cups of coffee a day were found more likely than other sedentary middle aged men to have high blood level of cholesterol, which is a factor increasing the risk of heart disease. Cholesterol can reach the blood from food and drink but it is not contained in coffee.
Which of the following, if true, most seriously weakens the conclusion from the study that for sedentary middle-aged men coffee coffee increases the risk of a heart attack?
a) A sedentary style of life increases levels of cholesterol in the blood.
b) Coffee contains caffeine, which acts as a stimulant and increases heart rate.
c) The men studied drank their coffee without milk or cream, which contains cholesterol.
d) In both groups, the men were likely to be overweight, and excess weight is a factor that increases the risk of heart disease.
e) The men who drank more than two cups of coffee a day also ate more foods high in cholesterol.
temperatures.
The correct answer is E(Highlight to reveal)
Let’s why.
Steps:
1)Read argument
2)Find the conclusion. The conclusion is:
For sedentary middle-aged men coffee increases the risk of a heart attack.
3)The argument is causal: Coffee -> increases blood cholesterol
4) We must show that something other than coffee increases blood cholesterol.
5) Choice E) shows that food may be an alternate cause. This weakens the conclusion.
Strengthening/Weakening Assignment
OG 11: 1, 3, 7, 9, 10, 12, 13, 15, 16, 18, 23, 26, 30, 33, 38, 43, 44, 48, 53, 54, 55, 63, 67, 72, 78, 83, 88, 93, 102, 103, 104, 113, 114, 115, 118, 121, 122, 123
Verbal Review: 1, 6, 15, 16, 17, 21, 22, 23, 24, 29, 30, 31, 32, 35, 36, 40, 48, 50, 54, 60, 67, 68, 69
(46)
(28)
(2)