Researchers studying athletes found that those who played mainly for the love of their sport actually had sharper vision during athletic competitions than those whose main goal was winning a trophy or championship. The vision of the first group of athletes was sharper because the concentration necessary for acute vision during an activity is typically possessed to a greater degree by those whose attention is focused on the activity itself.

Summary

Researchers found that athletes who played mainly for the love of their sport had sharper vision during competitions compared to athletes whose main goal was winning a trophy or championship. The first group had sharper vision because those whose attention is focused on an activity itself usually have more of the concentration necessary for acute vision.

Strongly Supported Conclusions

Athletes who play mainly for the love of their sport focus more on the activity itself than athletes whose main goal is winning a trophy or championship.

A
Winning a trophy or championship is not important to athletes who play mainly for the love of their sport.

This answer is unsupported. To say that winning a trophy or championship is not important at all is too extreme. We know that these athletes play mainly for the love of their sport, but this does not have to be the only reason they play.

B
If an athlete’s main goal during an athletic competition is winning a trophy or championship, that athlete will lack the concentration necessary for adequate vision during that competition.

This answer is unsupported. To say that these athletes will not have the concentration necessary is too extreme. We only know from the stimulus that these athletes possess this concentration to a lesser degree, not that they don’t possess it at all.

C
Athletes who play mainly for the love of their sport concentrate more on the sport itself during athletic competitions than do athletes whose main goal is winning a trophy or championship.

This answer is strongly supported. We know from the stimulus that the athletes who play for the love of their sport had sharper vision, and we know that this sharper vision comes from concentrating on the sport itself.

D
It is impossible for an athlete to concentrate on more than one thing at a time during an athletic competition.

This answer is unsupported. To say that it is impossible is too extreme. We know from the stimulus that athletes either mainly play for the love of their sport or wining a trophy. We can’t assume that having a main objective means that there are no other objectives.

E
During athletic competitions, an athlete whose attention is focused on the sport itself will perform better than any athlete whose attention is focused elsewhere.

This answer is unsupported. We don’t know anything about an athlete’s performance from the stimulus.


10 comments

Although human economic exchange predates historical records, it is clear that the very first economies were based on barter and that money came later. This can be inferred from occasions in history when, in isolated places, currency largely disappeared from the local economy. At such times, the economy typically reverts to the original barter system, but then quickly abandons this form of exchange when currency becomes available again.

Summarize Argument
The author concludes that the very first economies were based on barter, with money coming later. This is based on the premise that, during times when the use of money disappears in isolated places, the economy typically “reverts to the original barter system.” These places then go back to money when it becomes available again.

Identify and Describe Flaw
The argument uses circular reasoning. In asserting as a premise that when money disappears in isolated places, the economy typically “reverts to the original barter system,” the author presupposes that barter was the original system. The author is trying to prove that the very first economies were based on barter, not money. So, when supporting that conclusion, it’s not persuasive for the author to assume that barter was “the original” (very first) system. This simply assumes that the conclusion is already true.

A
The argument concludes that something can cause a particular outcome merely because it is necessary for that outcome.
The conclusion doesn’t assert any causal relationship. It simply asserts that the first economies were based on barter, and money came later. This doesn’t say barter caused money to come about, or that anything caused barter.
B
The argument contains premises that contradict one another.
The premises do not contradict each other. It can be true that when money disappeared, places turned to a barter economy. Then, when money was available again, the economy turned back into one based on money.
C
The argument presumes that something should be done merely because historically it has been done.
The conclusion doesn’t assert that anything “should” be done. The author does not issue a command or recommendation or display any kind of value judgment. The conclusion is simply a descriptive one concerning whether the first economies were barter-based or money-based.
D
The argument infers a causal relation between two events merely from the fact that one event occurred before the other.
The author does not conclude or assume any causal relationship. He simply asserts that the first economies were based on barter, and money came later. This doesn’t imply barter caused money to come about, or that anything caused barter.
E
The argument relies on a premise that presupposes what the argument attempts to show in the conclusion.
(E) accurately describes the circular reasoning of the argument. A premise, in describing how an economy “reverts to the original barter system” presupposes what the argument atttempts to show in the conclusion — that the very first economies were based on barter.

50 comments

Pulford: Scientists who study the remains of ancient historical figures to learn about their health history need to first ask themselves if their investigation is a legitimate scientific inquiry or is motivated by mere curiosity. An investigation into a private matter such as health history is justified only if it is done for the advancement of scientific knowledge.

Varela: You forget that curiosity is the root of scientific inquiry. Many great scientific discoveries were motivated by curiosity alone.

Summarize Argument: Counter-Position
Pulford concludes that scientists who study the remains of ancient people to learn about their health history should ask whether their investigation is motivated by legitimate science or is motivated by curiosity. This is because Pulford believe that investigations into health history of historical figures can be justified only if it’s done for the purpose of advancing scientific knowledge.
Varela points out that curiosity is the root of scientific inquiry, and that many great scientific discovered were motivated by only curiosity. (The implicit conclusion is that investigations into the healthy history of historical figures, even if motivated by mere curiosity, can still be a legitimate scientific inquiry.)

Describe Method of Reasoning
Varela questions a distinction Pulford drew between a study motivated by legitimate science and a study motivated only by curiosity.

A
contending that Pulford’s argument rests on an untenable distinction
Varela points out that curiosity is the root of scientific inquiry. This blurs the distinction between a study motivated by scientific inquiry adn a study motivated by curiosity.
B
disputing the validity of a principle that Pulford explicitly states
The principle Pulford states is that investigations into individuals’ health is justified only if it’s for the advancement of science. Varela doesn’t dispute this principle. He broadens the scope of “for the advancement of science” to include studies motivated by curiosity.
C
offering a counterexample to a generalization in Pulford’s conclusion
Varela doesn’t bring up a counterexample. He doesn’t bring up a scientist who doesn’t need to ask whether their investigation is a legitimate scientific inquiry or is motivated by curiosity.
D
attempting to draw a distinction between two views that Pulford treats as a single view
Pulford brings up his own view that scientists need to ask themselves about the purpose of their study into historical figures’ health. This does not combine two views. And Varela does not try to draw a distinction; he tries to collapse a distinction made by Pulford.
E
maintaining that Pulford’s argument is based on inconsistent premises
Varela does not assert that Pulford’s premises contradict each other. He interprets a distinction made by Pulford (between studies motivated by science and those motivated by curiosity) in a way that suggests the distinction is blurred.

32 comments

Doctor: Angiotensinogen is a protein in human blood. Typically, the higher a person’s angiotensinogen levels are, the higher that person’s blood pressure is. Disease X usually causes an increase in angiotensinogen levels. Therefore, disease X must be a cause of high blood pressure.

Summarize Argument: Phenomenon-Hypothesis

The doctor hypothesizes that disease X causes high blood pressure, because it typically increases angiotensinogen levels, which are linked to higher blood pressure.

Identify and Describe Flaw

This is the cookie-cutter flaw of assuming that correlation proves causation. The doctor shows that disease X usually causes higher angiotensinogen levels and that higher angiotensinogen levels are correlated with higher blood pressure. She then jumps to the conclusion that disease X causes high blood pressure. To do this, she must assume that higher angiotensinogen levels actually cause high blood pressure. However, it’s possible that high blood pressure causes higher angiotensinogen levels, or that another factor like smoking or genetics causes both.

A
It confuses a necessary condition for a sufficient condition.

This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The doctor doesn’t make this mistake; her argument relies on causal logic, not conditional logic.

B
It overlooks the possibility that even if a condition causally contributes to a given effect, other factors may fully counteract that effect in the presence of that condition.

The doctor’s argument is flawed because she assumes that angiotensinogen levels cause high blood pressure, not because she overlooks other factors that might counteract the effects of disease X.

C
It illicitly infers, solely on the basis of two phenomena being correlated, that one causally contributes to the other.

In order to conclude that disease X causes high blood pressure by raising angiotensinogen levels, the doctor must assume that high angiotensinogen levels cause high blood pressure. However, her argument only establishes that the two are correlated.

D
It confuses one phenomenon’s causing a second with the second phenomenon’s causing the first.

The only proven causal connection in the argument is that disease X usually causes higher angiotensinogen levels. The doctor doesn’t confuse this by saying that higher angiotensinogen levels cause disease X. Instead, she assumes that they cause high blood pressure.

E
It takes for granted that if one phenomenon often causes a second phenomenon and that second phenomenon often causes a third phenomenon, then the first phenomenon cannot ever be the immediate cause of the third.

This is descriptively inaccurate. The doctor says one phenomenon (disease X) causes a second phenomenon (higher angiotensinogen) and assumes that higher angiotensinogen causes high blood pressure. She then concludes that disease X is the immediate cause of high blood pressure.


18 comments

A scientific team compared gold samples from several ancient artifacts with gold samples from an ancient mine in western Asia. The ratios of the trace elements in these samples were all very similar, and they were unlike the trace-element ratios from any other known mine. It is therefore likely that the gold in the artifacts was dug from the ancient mine.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the gold in the ancient artifacts was likely dug from a certain ancient mine. This is based on the fact that ratios of trace elements in the gold in the artifacts is very similar to the ratios of those elements in gold from the mine, and no other known mine has those same ratios.

Notable Assumptions
The author assumes that the gold in the artifacts is likely to have come from a source that shares the same ratios of trace elements. The author also assumes that there are no other potential sources for the gold besides a mine.

A
The ancient mine tapped into a large underground deposit that also supplied nearby riverbeds with significant quantities of gold.
This provides a potential alternate source of the gold in the artifacts. The gold might have come, not from the ancient mine, but from nearby riverbeds. These riverbeds likely have the same element ratios as that of the ancient mine, because the gold is from the same deposit.
B
The ancient mine may have at one time been operated by the same civilization that was responsible for most of the ancient artifacts.
If anything, this might strengthen the argument by making the connection between the artifacts and the mine more plausible.
C
The ancient mine was first operated many centuries before the artifacts were constructed.
This might strengthen the argument by eliminating the possibility that the ancient mine wasn’t in existence when the artifacts were made.
D
Ancient gold artifacts were often constructed from gold taken from earlier artifacts.
This suggests the gold in the artifacts might have been taken from earlier artifacts. But this doesn’t affect the original source of the gold; it could have been dug from the ancient mine and simply used in various artifacts over the years.
E
Much of the gold dug from the ancient mine in western Asia was transported to faraway destinations.
If anything this might strengthen the argument by suggesting the gold in the mine could have spread far and been used to make various items, potentially including the artifacts that we’re talking about.

Further Explanation

Additional note to (A). With (A) being true, the premises now indicate clearly that the artifact gold originated from the somewhere in the network (large underground deposit) but not any specific node (mine or riverbeds). In fact, knowing that there are additional nodes (riverbeds) reduces the likelihood of the hypothesized node (mine) being the source.


34 comments