The manager of a nuclear power plant defended the claim that the plant was safe by revealing its rate of injury for current workers: only 3.2 injuries per 200,000 hours of work, a rate less than half the national average for all industrial plants. The manager claimed that, therefore, by the standard of how many injuries occur, the plant was safer than most other plants where the employees could work.

Summarize Argument
The manager concludes that the nuclear plant is safer than most other plants where the plant’s employees could work. As evidence, he cites the fact that the nuclear plant’s rate of injuries is less than half the national average for industrial plants.

Notable Assumptions
The manager assumes that a claim about safety can be derived solely from a statistic about injury rate. This means that he doesn’t believe the magnitude of each individual injury should be factored into any discussion of safety. The manager also assumes that injuries on the job are identified immediately, rather than later in life once employment has finished. It could be that the type of work required at nuclear plants exposes workers to harmful chemicals with latent effects, or that the work is physically demanding.

A
Workers at nuclear power plants are required to receive extra training in safety precautions on their own time and at their own expense.
Whether or not we know if other industrial plants have similar protocols in place, it’s hard to see how this could weaken the manager’s argument. If anything, it makes it possible nuclear power plants really are less dangerous than other plants.
B
Workers at nuclear power plants are required to report to the manager any cases of accidental exposure to radiation.
Like (A), we don’t know if this is true of other industrial plants, too. And like (A), this gives another reason why the manager may well be right about nuclear power plant safety.
C
The exposure of the workers to radiation at nuclear power plants was within levels the government considers safe.
This suggests that nuclear power plant workers aren’t experiencing an additional health risk that other industrial plant workers wouldn’t be exposed to. If anything, this helps the manager’s position.
D
Workers at nuclear power plants have filed only a few lawsuits against the management concerning unsafe working conditions.
It seems nuclear power plant workers don’t find working conditions particularly unsafe. This seems to support the manager’s claim that nuclear plants are relatively safe.
E
Medical problems arising from work at a nuclear power plant are unusual in that they are not likely to appear until after an employee has left employment at the plant.
While nuclear power plants have fewer injuries to report each year, the workers suffer nuclear-plant-unique medical problems once they leave their job at the plant. These problems may outweigh the statistic the manager cites.

77 comments

Joseph: My encyclopedia says that the mathematician Pierre de Fermat died in 1665 without leaving behind any written proof for a theorem that he claimed nonetheless to have proved. Probably this alleged theorem simply cannot be proved, since—as the article points out—no one else has been able to prove it. Therefore it is likely that Fermat was either lying or else mistaken when he made his claim.

Laura: Your encyclopedia is out of date. Recently someone has in fact proved Fermat’s theorem. And since the theorem is provable, your claim—that Fermat was lying or mistaken—clearly is wrong.

A
It purports to establish its conclusion by making a claim that, if true, would actually contradict that conclusion.

Laura’s premise doesn't support her conclusion well, but it doesn’t contradict her conclusion.

B
It mistakenly assumes that the quality of a person’s character can legitimately be taken to guarantee the accuracy of the claims that person has made.

Laura doesn’t make any claims or assumptions about the quality of Fermat’s character or how his character affects the accuracy of his claims.

C
It mistakes something that is necessary for its conclusion to follow for something that ensures that the conclusion follows.

In order for Laura’s conclusion— that Fermat was neither lying nor mistaken about proving the theorem— to follow, it is necessary that the theorem is actually provable. But the theorem being provable does not ensure that this conclusion follows.

D
It uses the term “provable” without defining it.

It’s true that Laura never defines the term “provable,” but this isn’t an error in her argument. She doesn’t need to define the term.

E
It fails to distinguish between a true claim that has mistakenly been believed to be false and a false claim that has mistakenly been believed to be true.

Laura doesn’t mention either of these kinds of claims, nor does she fail to distinguish between them. Joseph mistakenly believes a true claim— that the theorem is provable— to be false, but this doesn’t describe an error in Laura’s argument.


67 comments

Critic: Most chorale preludes were written for the organ, and most great chorale preludes written for the organ were written by J. S. Bach. One of Bach’s chorale preludes dramatizes one hymn’s perspective on the year’s end. This prelude is agonizing and fixed on the passing of the old year, with its dashed hopes and lost opportunities. It does not necessarily reveal Bach’s own attitude toward the change of the year, but does reflect the tone of the hymn’s text. People often think that artists create in order to express their own feelings. Some artists do. Master artists never do, and Bach was a master artist.

Summary

Bach was a master artist. Master artists never create music to express their feelings, but other artists (i.e., some non-master artists) do. This can be diagrammed as follows:

Notable Valid Inferences

Bach never created music to express his feelings. This means the chorale prelude discussed in the stimulus was not made to reveal Bach’s attitudes toward the change of the year.

A
Bach believed that the close of the year was not a time for optimism and joyous celebration.

This could be true. The stimulus doesn’t offer information on how Bach felt about the year ending. While his prelude on this topic wasn’t celebratory, we know that Bach’s music wasn’t designed to express his feelings.

B
In composing music about a particular subject, Bach did not write the music in order to express his own attitude toward the subject.

This must be true. Bach was a master artist, which implies that he never created music to express his feelings.

C
In compositions other than chorale preludes, Bach wrote music in order to express his feelings toward various subjects.

This must be false. Master artists such as Bach never create music to express their feelings. If someone does create music to express their feelings, they must not be a master artist, and therefore must not be Bach, as shown in the diagram below.

D
Most of Bach’s chorale preludes were written for instruments other than the organ.

This could be true. While we know that most great chorale preludes written for the organ were composed by Bach, we don't have information about his preludes for other instruments. Bach's organ preludes may have been fewer in number compared to his preludes for other instruments.

E
Most of the great chorale preludes were written for instruments other than the organ.

This could be true. We know there are some great chorale preludes written specifically for the organ—we don’t know how these compare in number to the great chorale preludes for other instruments.


53 comments

Terry: Some actions considered to be bad by our society have favorable consequences. But an action is good only if it has favorable consequences. So, some actions considered to be bad by our society are actually good.

Pat: I agree with your conclusion, but not with the reasons you give for it. Some good actions actually do not have favorable consequences. But no actions considered to be bad by our society have favorable consequences, so your conclusion, that some actions our society considers bad are actually good, still holds.

Terry says that some actions considered to be bad by our society are actually good. As premises, he gives two conditional claims, shown in the diagram below. Pat arrives at the same conclusion, that some actions considered to be bad by our society are actually good, but he arrives at this conclusion by citing two different conditional claims, shown in the diagram below.

Identify and Describe Flaw
Both speakers commit the cookie-cutter “confusing sufficiency and necessity” flaw. Terry mistakenly argues that since some bad actions and all good actions share the necessary condition of favorable consequences, some actions considered bad are actually good. Alternatively, Pat mistakenly argues that because some good actions and all bad actions share the necessary condition of not having good consequences, some actions considered bad are actually good.

A
presupposing that if a certain property distinguishes one type of action from another type of action, then that property is one of many properties distinguishing the two types of action
Neither Terry nor Pat makes assumptions about the number of properties distinguishing actions. They only argue that some actions considered bad by our society are actually good.
B
presupposing that if most actions of a certain type share a certain property, then all actions of that type share that property
This is a cookie-cutter flaw of confusing “most” for “all.” Neither Terry nor Pat discusses “most” actions of any type.
C
presupposing that if a certain property is shared by actions of a certain type in a given society, then that property is shared by actions of that type in every society
Neither Terry nor Pat discusses “every” society. Both Terry and Pat only argue that some actions considered to be bad by our society are actually good.
D
presupposing that if an action’s having a certain property is necessary for its being a certain type of action, then having that property is sufficient for being that type of action
This is the cookie-cutter “confusing sufficiency and necessity” flaw committed by both Terry and Pat. They both draw unfounded conclusions about two sufficient conditions because those sufficient conditions share a necessary condition.
E
presupposing that if a certain property is shared by two types of action, then that property is the only property distinguishing the two types of action from actions of other types
Neither Terry’s argument nor Pat’s argument addresses the number of properties distinguishing any actions. Both Terry and Pat just argue that some actions considered to be bad by our society are actually good.

103 comments