Section Types Logical Reasoning

LSAT 29 - Section 1 - Question 16

December 8, 2012

To see how (B) weakens the argument, we need to first understand the assumptions the argument makes.

[Premise 1] Language tells us something about living conditions.
[Premise 2] PIE didn't have a word for "sea". PIE did have words for "winter", "snow", and "wolf".

[Conclusion] PIE people lived in a cold place isolated from the sea.

Do you see how useless Premise 1 actually is? Of course language tells us something about living conditions. You don't need to say that because it's obvious.

Instead, what I need to know, in order for Premise 1 to hook up with Premise 2, is specifically what it is that language tells me about living conditions. Specifically, I need to know that if a language had a word for something, then the feature that word points to existed in the living conditions of the people who spoke that language. (Had the word "winter" which points to a cold season, so PIE people lived in a place with cold seasons. Had the word "snow" which points to snow, so PIE people lived in a cold place. Had the word "wolf" which points to wolf and wolves are awesome.)

I also need to know that if a language lacked a word for something, then the feature that missing word points to did not exist in the living conditions of the people who spoke that language. (Missing the word "sea" which points to sea, so PIE people lived in a place with no sea.)

Those are the huge universal assumptions about the evidentiary power of language that the argument makes. (B) denies those assumptions. It denies universality. It makes the premises less supportive of the conclusion.

(B) doesn't claim whether PIE falls into its group. I know you want to say "we have to assume that PIE is one of those languages in (B)" but you don't. You don't because you don't have to prove the conclusion wrong (and you're trying to do that). Your job is only to make the existing premises less supportive of the conclusion.

That's a distinction introduced way back in the original Core Curriculum lessons on how to weaken arguments. Do not attack the conclusion. Attack the support the premises lend to the conclusion. In other words, wreck the assumptions.

LSAT 107 - Section 1 - Question 16

December 8, 2012

To see how (B) weakens the argument, we need to first understand the assumptions the argument makes.

[Premise 1] Language tells us something about living conditions.
[Premise 2] PIE didn't have a word for "sea". PIE did have words for "winter", "snow", and "wolf".

[Conclusion] PIE people lived in a cold place isolated from the sea.

Do you see how useless Premise 1 actually is? Of course language tells us something about living conditions. You don't need to say that because it's obvious.

Instead, what I need to know, in order for Premise 1 to hook up with Premise 2, is specifically what it is that language tells me about living conditions. Specifically, I need to know that if a language had a word for something, then the feature that word points to existed in the living conditions of the people who spoke that language. (Had the word "winter" which points to a cold season, so PIE people lived in a place with cold seasons. Had the word "snow" which points to snow, so PIE people lived in a cold place. Had the word "wolf" which points to wolf and wolves are awesome.)

I also need to know that if a language lacked a word for something, then the feature that missing word points to did not exist in the living conditions of the people who spoke that language. (Missing the word "sea" which points to sea, so PIE people lived in a place with no sea.)

Those are the huge universal assumptions about the evidentiary power of language that the argument makes. (B) denies those assumptions. It denies universality. It makes the premises less supportive of the conclusion.

(B) doesn't claim whether PIE falls into its group. I know you want to say "we have to assume that PIE is one of those languages in (B)" but you don't. You don't because you don't have to prove the conclusion wrong (and you're trying to do that). Your job is only to make the existing premises less supportive of the conclusion.

That's a distinction introduced way back in the original Core Curriculum lessons on how to weaken arguments. Do not attack the conclusion. Attack the support the premises lend to the conclusion. In other words, wreck the assumptions.

We can learn about the living conditions of a vanished culture by examining its language. Thus, it is likely that the people who spoke Proto-Indo-European, the language from which all Indo-European languages descended, lived in a cold climate, isolated from ocean or sea, because Proto-Indo-European lacks a word for “sea,” yet contains words for “winter,” “snow,” and “wolf.”

Summarize Argument: Phenomenon-Hypothesis

The author hypothesizes that the ancient culture who spoke Proto-Indo-European lived in a cold climate away from the ocean. This hypothesis is based on applying the principle that we can learn about ancient peoples through their languages to Proto-Indo-European. The language has words for “winter,” “snow,” and “wolf,” but does not have a word for “sea,” leading to the hypothesis that its speakers lived near winter, snow, and wolves (i.e. in a cold climate), but not the sea.

Notable Assumptions

The author assumes that just because we can learn about a culture from its language, the words of an ancient language will correspond exactly to its speakers’ location. In other words, the author assumes that ancient languages have words for every environmental feature of the speakers’ location, and don’t have words for features absent from the speakers’ location.

A

A word meaning “fish” was used by the people who spoke Proto-Indo-European.

This does not weaken the argument, because having a word for “fish” is entirely consistent with the author’s hypothesis and assumptions. Fish can be found in freshwater in a cold climate just as easily as in the sea or in a warm climate, so this doesn’t tell us anything new.

B

Some languages lack words for prominent elements of the environments of their speakers.

This weakens the argument, because it suggests that a language can lack a word for “sea” even if its speakers live near the sea. That undermines the support for the author’s hypothesis, and so weakens the argument.

C

There are no known languages today that lack a word for “sea.”

This does not weaken the argument. The scope of the argument is limited to what we can learn based on the language of a vanished culture, so features of modern languages aren’t really relevant. This just doesn’t impact the argument.

D

Proto-Indo-European possesses words for “heat.”

This does not weaken the argument. Having words for “heat” is perfectly consistent with the author’s assumption, because even cold environments contain some heat—for instance, summer, fire, or even body heat. So this doesn’t undermine the author’s argument.

E

The people who spoke Proto-Indo-European were nomadic.

This doesn’t weaken the argument, because a people being nomadic still doesn’t guarantee which environmental features they will and won’t encounter. The author’s argument could apply to the range of a nomadic people as easily as the fixed location of a sedentary people.

LSAT 25 - Section 4 - Question 11

December 8, 2012

LSAT 102 - Section 4 - Question 11

December 8, 2012

Taken together, some 2,000 stocks recommended on a popular television show over the course of the past 12 years by the show’s guests, most of whom are successful consultants for multibillion-dollar stock portfolios, performed less successfully than the market as a whole for this 12-year period. So clearly, no one should ever follow any recommendations by these so-called experts.

Summarize Argument

The author concludes that no one should take the advice of so-called expert stock consultants. This is because 2,000 of the stocks such experts recommended on a TV show over the last 12 years performed worse than the market did over the same period.

Notable Assumptions

The author assumes that these 2,000 stocks are reflective of what the consultants recommend in general, without considering other stocks that may have also been recommended and performed well. The author also assumes that performance over this certain 12-year period is sufficient to draw conclusions about the consultants’ abilities to predict which stocks will do well. Perhaps the period in question was anomalous for some reason, or perhaps the stocks won’t pay off until a later date.

A

Taken together, the stocks recommended on the television show performed better than the market as a whole for the past year.

Evidently, it’s sometimes a good idea to take the consultants’ advice. Last year, their stocks outperformed the market.

B

Taken together, the stocks recommended on the television show performed better for the past 12-year period than stock portfolios that were actually selected by any other means.

Since you can’t buy the market itself, you have to put together a portfolio. Those portfolios all performed even worse than those selected by the consultants, meaning their advice was worthwhile.

C

Performance of the stocks recommended on the television show was measured by stock dividends, whereas the performance of the market as a whole was measured by change in share value.

The way the stocks and the market were measured differed. This means a comparative conclusion can’t be drawn about them.

D

Performance of the stocks recommended on the television show was measured independently by a number of analysts, and the results of all the measurements concurred.

Several different measurements confirmed the stocks recommended on the TV show performed worse than the market. This certainly doesn’t weaken the claim that the so-called expert consultants aren’t giving good advice.

E

The stock portfolios for which the guests were consultants performed better for the past 12-year period than the market as a whole.

Even if the recommended stocks didn’t all do well together, the consultants were nevertheless able to create decent portfolios using different combinations of stocks. This suggests their advice may be worthwhile.

LSAT 25 - Section 2 - Question 15

December 8, 2012

LSAT 102 - Section 2 - Question 15

December 8, 2012

Some plants have extremely sensitive biological thermometers. For example, the leaves of rhododendrons curl when the temperature of the air around them is below 0(C (Celsius). Similarly, mature crocus blossoms open in temperatures above 2(C. So someone who simultaneously observed rhododendrons with uncurled leaves, crocuses with mature but unopened blossoms, and a thermometer showing 1(C could determine that the thermometer’s reading was accurate to within plus or minus 1(C.

Summarize Argument

The author concludes that someone observing two separate plant phenomena would be able to determine that a thermometer reading is correct to within plus or minus one degree celsius.

Notable Assumptions

The author assumes that air temperatures are consistent in the observed area. Since crocuses open above two degrees, the temperature around the crocuses has to be below two degrees for the crocuses. But the rhododendrons would remain uncurled at any temperature above zero degrees, which means the air around them could be well above two degrees.

A

Neither rhododendrons nor crocuses bloom for more than a few weeks each year, and the blossoms of rhododendrons growing in any area do not appear until at least several weeks after crocuses growing in that area have ceased to bloom.

This is saying that our hypothetical is impossible, but that doesn’t matter. We’re concerned about weakening the argument using the hypothetical.

B

Many people find it unpleasant to be outdoors for long periods when the temperature is at or about 1(C.

Again, we’re dealing with a hypothetical. We don’t care whether the hypothetical thermometer-holder likes being out in the cold.

C

The climate and soil conditions that favor the growth of rhododendrons are also favorable to the growth of crocuses.

It doesn’t matter how these plants grew. We care about a specific instance of using the plants’ biological thermometers to test a real thermometer.

D

Air temperature surrounding rhododendrons, which can grow 12 feet tall, is likely to differ from air temperature surrounding crocuses, which are normally only a few inches high, by more than 2(C, even if the two plants are growing side by side.

Since the air temperature surrounding the two plants is likely to differ, we can’t use the plants’ reactions to the temperature to gauge if the thermometer reading is right. The plants might be reacting to different temperatures.

E

Certain types of thermometers that are commonly used to measure outdoor temperatures can be extremely accurate in moderate temperature ranges but much less accurate in warmer or colder temperature ranges.

We don’t know what a “moderate” temperature is. Zero degrees? Twenty degrees? Besides, we’re using the plants’ reactions to the temperature to gauge if the thermometer is accurate. That’s the whole point of the hypothetical.

LSAT 21 - Section 2 - Question 17

December 8, 2012

LSAT 23 - Section 2 - Question 08

December 8, 2012

LSAT June 2007 - Section 2 - Question 14

November 30, 2012

Relevant lessons: Phenomenon-hypothesis questions | Weakening Questions

LSAT 123 - Section 2 - Question 14

November 30, 2012

Relevant lessons: Phenomenon-hypothesis questions | Weakening Questions

A cup of raw milk, after being heated in a microwave oven to 50 degrees Celsius, contains half its initial concentration of a particular enzyme, lysozyme. If, however, the milk reaches that temperature through exposure to a conventional heat source of 50 degrees Celsius, it will contain nearly all of its initial concentration of the enzyme. Therefore, what destroys the enzyme is not heat but microwaves, which generate heat.

Summarize Argument: Phenomenon-Hypothesis

The author hypothesizes that microwaves rather than heat kill an enzyme in milk. He bases this on the difference in enzyme concentration between milk heated in a microwave and milk heated through a conventional source.

Notable Assumptions

The author assumes that the two methods of heating—microwaves and conventional heat sources—are in all ways comparable, hence why microwaves themselves are to blame for the enzyme reduction. This means that the author doesn’t believe that some difference in the heating methods (e.g. time it takes to reach 50 degrees Celsius) accounts for the difference in enzyme concentration.

A

Heating raw milk in a microwave oven to a temperature of 100 degrees Celsius destroys nearly all of the lysozyme initially present in that milk.

We don’t care what happens at 100 degrees Celsius. We need to weaken the author’s hypothesis about milk heated to 50 degrees Celsius.

B

Enzymes in raw milk that are destroyed through excessive heating can be replaced by adding enzymes that have been extracted from other sources.

The author hypothesizes about what causes milk to lose its enzymes. We’re not interested in how those enzymes can be replenished.

C

A liquid exposed to a conventional heat source of exactly 50 degrees Celsius will reach that temperature more slowly than it would if it were exposed to a conventional heat source hotter than 50 degrees Celsius.

The stimulus talks about a heat source of 50 degrees Celsius. We’re not interested in other ranges.

D

Milk that has been heated in a microwave oven does not taste noticeably different from milk that has been briefly heated by exposure to a conventional heat source.

Taste is irrelevant. We’re talking about enzymes.

E

Heating any liquid by microwave creates small zones within it that are much hotter than the overall temperature that the liquid will ultimately reach.

While milk is heated to 50 degrees Celsius in the microwave, pockets reach higher temperatures that thus kill the enzymes. This shows that microwaves themselves don’t kill enzymes—instead, high heat does.

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