Commentator: The worldwide oil crisis of 1973 was not due to any real shortage of oil, but was the result of collusion between international oil companies and oil-producing countries to artificially restrict the supply of oil in order to profit from higher prices. This is shown by the fact that after 1973 the profits of oil companies showed large increases, as did the incomes of oil-producing countries.

Summarize Argument: Phenomenon-Hypothesis
The author concludes that the oil crisis of 1973 was due to collusion between oil companies and oil-producing countries. This is based on the fact that after 1973, the profits of oil companies increased, and the incomes of oil-producing companies also increased.

Identify and Describe Flaw
The author assumes that because oil companies and oil-producing countries benefited from the oil crisis, that they must have played a role in causing the oil crisis. This overlooks the possibility that they simply benefited from an event that they did not cause.

A
fails to consider the possibility that a party can benefit from an event without helping to bring about that event
This possibility shows why the conclusion doesn’t follow from the premises. If something can benefit from an event without helping to cause it, then the fact certain companies and countries benefited from the oil crisis does not prove that they caused it.
B
presumes, without providing justification, that oil companies and oil-producing countries were the only parties to benefit from the 1973 oil crisis
If other parties benefited, too, that doesn’t undermine the argument’s reasoning. The author might believe those other parties were also contributory factors in the oil crisis of 1973.
C
rests on using the term “profit” in an ambiguous way
The word “profit” is not used to mean two different things. “Profit” is used to mean financial gain.
D
fails to establish that there was a worldwide oil surplus prior to the crisis of 1973
There is no need to establish that there was a surplus in order to show that certain parties caused a reduction in available oil later.
E
fails to consider the possibility that events that occur simultaneously can be causally related
The author doesn’t overlook this possibility. In fact, the author’s conclusion assumes that the increased profits and income of oil companies and oil-producing countries are causally related to each other.

5 comments

In a study, six medical students were each separately presented with the same patient, whose symptoms could be the result of any one of several medical conditions. The attending physician asked each student a leading question of the form, “What tests should we order to try to rule out a diagnosis of X?” where X was filled in with a different medical condition for each student. A week later each student was presented with a patient having similar symptoms in the presence of a different attending physician who asked for a diagnosis without asking any leading questions. Each student began by testing the diagnosis that had been suggested by the original attending physician.

Summary
In a study, six medical students were presented with the same patient. The attending physician asked each student a leading question in the form, “What tests should we order to try to rule out diagnosis X?” For each student, the physician stated a different medical condition for X. A week later each student was presented a second patient with similar symptoms, but a different attending physician did not ask any leading questions. Each student tested for the diagnosis that had been suggested by the first attending physician.

Strongly Supported Conclusions
None of the medical students tested for the same diagnosis as each other when diagnosing the second patient.

A
On the second occasion, none of the medical students began by testing the same diagnosis as any of the other medical students.
This answer is strongly supported. On the first occasion, the attending physician suggested a different diagnosis to each medical student. Therefore, each student tested for a different diagnosis on the second occasion.
B
At most one of the medical students knew which of the several medical conditions was most likely to lead to the patients’ symptoms.
This answer is unsupported. We don’t have any information from the stimulus about the knowledge of any of the medical students. We only know about the actions the medical students took.
C
The second attending physician was unaware of the results of the students’ encounter with the first attending physician.
This answer is unsupported. We don’t know from the stimulus whether the second attending physician was aware or unaware of the first occasion.
D
On the second occasion, exactly one of the students tested for the medical condition that actually caused the patient’s symptoms.
This answer is unsupported. We don’t know from the stimulus whether any of the diagnoses the medical students tested were correct.
E
At least some of the medical students were unaware that the patients’ symptoms could be the result of medical conditions other than the one suggested by the original attending physician.
This answer is unsupported. We don’t know anything about the medical students’ awareness or knowledge from the stimulus. It could be the case that the medical students were aware but nevertheless followed the attending physician’s suggestions.

25 comments

Few, if any, carbonated beverages contain calcium. Some very popular ones, however, contain significant amounts of caffeine, and consuming caffeine causes people to excrete significantly more calcium than they would otherwise. Interestingly, teenagers who drink large amounts of carbonated beverages containing caffeine tend to suffer more broken bones than those who do not. Calcium deficiency can make bones more brittle, of course, so the higher incidence of broken bones in teenagers who consume carbonated beverages with caffeine is probably due primarily to caffeine consumption.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the correlation observed in teenagers between between broken bones and drinking carbonated beverages with caffeine is due to caffeine consumption. The author supports this hypothesis by the fact that caffeine causes people to excrete a lot of calcium, and calcium deficiency can make bones more brittle.

Notable Assumptions
The author assumes that the main factor causing the correlation observed in teenagers between broken bones and consumption of carbonated beverages is caffeine consumption. The author also assumes that if teenagers who drink carbonated beverages with caffeine have calcium deficiency, that this is mainly due to the beverages rather than some other cause.

A
Teenagers who drink large quantities of carbonated beverages containing caffeine tend to drink smaller quantities of calcium-rich beverages than other teenagers do.
This provides an alternate explanation for the correlation between broken bones and the beverage consumption. If teens who drink the beverage drink less calcium-rich beverages (ex. milk) than other teens, the disparity in calcium-rich beverages could be the primary causal factor.
B
Teenagers engage in the types of activities that carry a high risk of causing broken bones much more often than both older and younger people do.
This compares teenagers vs. older people. We want a comparison between teenagers who drink the caffeine-rich carbonated beverages and teenagers who don’t drink the beverages.
C
Some teenagers have calcium deficiencies even though they do not consume any caffeine.
The author never assumed that calcium deficiency can never be caused by anything else besides caffeine consumption. The author’s theory requires only that caffeine consumption increases the likelihood that a child will have calcium deficiency and broken bones.
D
Some of the less popular carbonated beverages contain even more caffeine than the more popular ones.
The correlation and the conclusion do not make any distinction between different kinds of carbonated beverages with caffeine.
E
The more calcium a person ingests as a regular part of his or her diet, the more calcium that person will tend to excrete.
So, eating more calcium leads to more excretion of calcium. This doesn’t change the fact that eating caffeine causes people to excrete a lot more calcium than they otherwise would.

38 comments

Philosopher: Groups are not the type of entity that can be worthy of praise or blame. Blameworthiness implies conscience and agency. Nations do not have consciences. Families are not agents. Hence, any ascription of praise or blame to a group must be translated into some statement about individuals if we are to evaluate it properly.

Summarize Argument
Attributing the quality of praise or blame to a group must be translated into a statement about individuals. Why? Because groups cannot be worthy of praise or blame. Blameworthiness requires conscience and agency. Nations and families, for example, possess neither of these qualities.

Identify Argument Part
The claim in the third sentence is used as support for a sub-conclusion, which supports the Philosopher’s main conclusion.

A
It is an intermediate conclusion offered as direct support for the argument’s main conclusion.
The claim is not a sub-conclusion. The claim is used as support for a sub-conclusion in the Philosopher’s argument.
B
It is offered as support for an intermediate conclusion that is in turn offered as direct support for the argument’s main conclusion.
The claim supports a sub-conclusion in the Philosopher’s argument.
C
It is cited as an implication of the main conclusion drawn in the argument.
The claim is not an implication the Philosopher is inferring. The claim is stated as fact.
D
It is cited as an instance of a general conclusion drawn in the argument.
The claim does not directly support the Philosopher’s main conclusion.
E
It is the main conclusion drawn in the argument.
The claim is not the Philosopher’s main conclusion.

25 comments

Psychiatrist: Psychological stress is known both to cause negative emotions and to impair physical health. This suggests that overcoming such negative emotions when they arise could cause one’s health to improve.

Summarize Argument
The author concludes that overcoming negative emotions can cause one’s health to improve. This is based on the fact that stress is known to cause both negative emotions and worse health.

Identify and Describe Flaw
The author assumes that negative emotions cause worse health, simply because both are caused by stress. This overlooks the possibility that two things can have no causal impact on each other, even though they are both effects of a common cause.

A
It presumes without justification that two conditions that together have a certain effect causally influence one another.
The author doesn’t present “two conditions that together have a certain effect.” We’re not told that negative emotions and worse healthy together have some other effect.
B
It presumes, merely on the basis that two conditions have a common cause, that one of these two conditions can causally influence the other.
The author assumes, merely because both negative emotions and worse health have a common cause (stress), that negative emotions causally infuence health.
C
It confuses two causes that together are necessary to bring about an effect with causes that are sufficient for that effect.
The author doesn’t present “two causes that together are necessary to bring about an effect.” We’re not told that negative emotions and worse health are necessary to cause something else.
D
It takes for granted that two conditions that together have a certain effect can, each by itself, produce the same effect.
The author doesn’t present “two conditions that together have a certain effect.” We’re not told that negative emotions and worse health togethr produce an effect.
E
It takes for granted that removing a condition that causally contributes to another condition suffices to eliminate the latter condition.
The author doesn’t establish that negative emotions cause worse health. In addition, the author doesn’t conclude that overcoming negative emotions will “eliminate” any health impairments, only that it will help one’s health improve.

11 comments

Some potential anticancer drugs work by depriving growing tumors of needed blood vessels. The creation of blood vessels is called angiogenesis, and the experimental drugs work by inhibiting this process. The same drugs have been found to prevent obesity in rodents.

Summary
Some anticancer drugs work by depriving tumors of needed blood vessels. The drugs work by prohibiting angiogenesis, which is the creation of blood vessels. The same drugs have been discovered to prevent obesity in rodents.

Strongly Supported Conclusions
Angiogenesis is necessary for fat cells to grow.

A
The cells in tumors are more similar in structure to fat cells than to other cells in the body.
This answer is unsupported. We don’t know what the structure is of any kind of cell.
B
Drugs that inhibit angiogenesis would probably enable obese humans to lose weight.
This answer is unsupported. We don’t know if these drugs would probably cause obese humans to lose weight. We only know that the drugs have been found to prevent obesity in rodents.
C
Fat tissue depends on angiogenesis in order to grow.
This answer is strongly supported. Since the drugs prevent obesity in rodents, the drugs probably do this by inhibiting angiogenesis.
D
Rodents with cancer are more likely to be obese than healthy rodents.
This answer is unsupported. We don’t know anything about rodents with cancer.
E
Drugs that inhibit angiogenesis also prevent absorption of vital nutrients.
This answer is unsupported. We don’t know if the drugs have any other effects besides inhibiting angiogenesis.

32 comments