Summary
Reproduction for all species of higher animals requires the production of eggs, but not necessarily sperm. There are some species whose members are all female; the eggs produced by a rare famale-only salamander species hatch without fertilization. This has the drawback that all offspring have genetic codes nearly identical to that of the single parent, causing the species to be less adaptive than species with both male and female members.
Notable Valid Inferences
Some species of higher animals do not produce eggs.
A
There are some species of salamanders that have both male and female members.
Could be true. We know that a rare female-only species of salamander exists, but there could also be other species of salamander with both male and female members.
B
There are some species of higher animals none of whose members produce eggs.
Must be false. The first sentence tells us that reproduction for all higher animals requires the production of eggs.
C
There is a significant number of female-only species of higher animals.
Could be true. We know that a rare female-only species of salamander exists. It could be the case that there are many other female-only species.
D
Some species of higher animals containing both female and male members are not very adaptive.
Could be true. We know that female-only species are less adaptive than species with both male and female members, but this does not preclude the possibility of a species with both males and females that is also not very adaptive.
E
Some offspring of species of higher animals containing both female and male members have genetic codes more similar to one parent than to the other parent.
Could be true. We know that for female-only species offspring have genetic codes identical to the single parent. It is possible that some offspring of species with both males and females have genetic codes more similar to one parent.
Summarize Argument
TV executives argue that advertising will be no harder to sell next fall than last fall. This is because, despite the increase in price per advertisement, advertisers will still profit from TV advertising.
Notable Assumptions
The TV executives assume that the cost of running advertisements won’t also increase. Assuming advertisers are operating on the margins, even a minor uptick in expenses combined with the 10-15% increase would make advertising unprofitable. Alternately, the TV executives may assume that the 10-15% increase is counterbalanced by something else (i.e. increasing viewership).
A
Most costs of production and distribution of products typically advertised on television are expected to rise 3 to 7 percent in the next year.
This weakens the TV executives’ argument. Everything’s getting more expensive, so advertising might be one place to cut costs.
B
The system for rating the size of the audience watching any given television advertisement will change next fall.
No matter how the audience is “rated,” the audience will nevertheless be comprised of the same number of people. We care to know if that audience is growing, but this doesn’t tell us anything about that.
C
Next fall advertising time on television will no longer be available in blocks smaller than 30 seconds.
This says that in all likelihood, some advertisers must commit to longer advertisements than they’ve previously ran. This would make advertising more difficult to sell, thus weakening the TV executives’ argument.
D
The amount of television advertising time purchased by providers of services is increasing, while the amount of such time purchased by providers of products is decreasing.
We don’t care who buys the advertising.
E
A recent survey has shown that the average number of hours people spend watching television is increasing at the rate of 2 percent every two months.
Viewership is increasing. By the end of the year, viewership will be 12% higher than the start of the year. That mostly or totally offsets the advertising price increase for advertisers on a per-viewer basis.
TV talk show host: Well, if there is such a decline, it’s not because of TV talk shows: we simply show people what they want to see. What can be wrong with letting the viewers decide? Furthermore, if restrictions were put on my show, that would amount to censorship, which is wrong.
Speaker 1 Summary
The moralist concludes that TV talk shows are contributing to moral decline. This is because the shows portray the least moral people, which makes viewers think being immoral is normal and that there’s something wrong with being morally upstanding.
Speaker 2 Summary
The host’s implicit conclusion is that there’s nothing wrong with what her TV talk show is doing. She asserts that any moral decline, if it exists, isn’t caused by TV talk shows. She also asserts that there’s nothing wrong with letting viewers decide what they want see. Additionally, she claims that any restrictions on her show would be censorship, and therefore wrong.
Objective
We’re looking for a point of disagreement. The speakers disagree about whether TV shows are a cause of moral decline. The moralist thinks they are, and the host thinks they’re not.
A
TV talk shows should be censored
The moralist doesn’t express an opinion. Although the moralist thinks TV talk shows cause moral decline, that doesn’t mean the moralist thinks anything should be done about it. We just don’t know his opinion.
B
people’s moral standards have changed
The host doesn’t express an opinion. She says that if there’s a moral decline, TV talk shows aren’t a cause of it. She doesn’t say whether there actually is a moral decline or moral change.
C
TV talk shows influence people’s conception of what is the norm
Not a point of disagreement. The host doesn’t comment on whether TV talk shows influence the viewers. Although she does say that shows simply portray what people want to see, that doesn’t mean the host thinks the shows have no impact on viewers’ conception of what’s normal.
D
TV talk shows, by presenting immoral guests, are causing a moral decline
This is a point of disagreement. The moralist thinks TV talk shows do cause a moral decline by presenting immoral guests. The host does not think TV talk shows cause a moral decline.
E
it is wrong not to let the viewers decide what they want to see
The moralist expresses no opinion. Although she states that TV talk shows are causing a moral decline, that doesn’t tell us what she thinks about restricting what viewers can watch. Maybe she’s opposed to putting restrictions on shows, just like the host is.
Summarize Argument
The doctor thinks that the mere claim that some treatment is better than no treatment is not enough of a reason to support using a certain therapy to treat an illness. To support this, the doctor tells us that the therapy is expensive and complicated. This introduces additional factors that might make the therapy not worth it, even if the alternative is no treatment at all.
Identify Conclusion
The doctor’s conclusion is that using the therapy “cannot be adequately supported” just because it represents some treatment rather than no treatment at all.
A
The therapy is more effective than no treatment at all for the illness.
This is not stated in the argument. The doctor never actually mentions whether the therapy is effective or not, and nothing in the argument would support an inference that it’s effective.
B
The therapy is more effective than other forms of treatment for the illness.
This is not stated in the argument. Like (C), the doctor does not discuss any other possible treatments, so cannot compare them to the therapy that is discussed.
C
The therapy is more expensive and complicated than other forms of treatment for the illness.
This is not stated in the argument. Like (B), the doctor does not discuss any other possible treatments, so cannot compare them to the therapy that is discussed.
D
The therapy should not be used to treat the illness unless it is either effective or inexpensive.
This is not stated in the argument. The doctor doesn’t make any recommendations about when the therapy “should” or “should not” be used, just says that a certain claim isn’t sufficient to justify its use.
E
The therapy’s possible effectiveness in treating the illness is not sufficient justification for using it.
This is a good paraphrase of the conclusion. The doctor’s entire goal is to support this claim, that just because the therapy is some treatment rather than no treatment, that isn’t enough to justify its use.
Summarize Argument
This author concludes that Scottish druid stones are not very old. He supports this statement by saying that Irish druid stones are very old.
Identify and Describe Flaw
Our author identifies two groups of druid stones: Irish and Scottish. He tells us that all Irish stones are very old. That conditional relationship might look like this: Irish → Very Old.
Then, our author concludes that because Scottish stones are not Irish, they cannot have the characteristic of being very old (/Irish → /Very Old). The author commits the cookie-cutter flaw of confusing the necessary and sufficient conditions. All that the author has told us is that Irish druid stones are very old; he hasn’t ruled out the possibility of another type of stone also being very old. Therefore, the author’s argument is unsupported.
Then, our author concludes that because Scottish stones are not Irish, they cannot have the characteristic of being very old (/Irish → /Very Old). The author commits the cookie-cutter flaw of confusing the necessary and sufficient conditions. All that the author has told us is that Irish druid stones are very old; he hasn’t ruled out the possibility of another type of stone also being very old. Therefore, the author’s argument is unsupported.
A
allows a key term to shift in meaning from one use to the next
This is the cookie-cutter flaw of equivocation, where an author will argue a point hinged on a word that changes meaning. Our author doesn’t use terms that shift in meaning. The meaning of important terms in this argument stays consistent throughout.
B
takes the fact that most members of a group have a certain property to constitute evidence that all members of the group have that property
The author does not make a leap from most to all of a group in his argument; rather, he confuses the necessary and sufficient conditions.
C
takes for granted the very claim that it sets out to establish
This is a cookie-cutter answer choice referring to circular reasoning. For this to be the correct answer choice, our author would have had to assume or claim in his premises that Scottish druid stones are not very old. The author didn’t do that, so this is not correct.
D
presumes without justification that what was true of the members of a group in the past will continue to be true of them in the future
The author is not making predictions of the characteristics of future druid stones in their argument, but instead confusing the necessary and sufficient conditions.
E
takes the fact that all members of a group have a certain property to constitute evidence that the members of the group are the only things with that property
Our author establishes that all members of a group (the Irish druid stones) have a property (being very old), and uses this to say that something outside of the group (Scottish druid stones) cannot have that property (conclusion of Scottish stones not being very old).
Sheila: That is a bad idea. People who are driving too fast can easily lose control of their vehicles when they hit a speed bump.
Summarize Argument: Counter-Position
In response to Robert’s claim that the city of Crownsbury should install speed bumps on streets to slow down speeding drivers, Sheila concludes that this approach is a bad idea. To support her claim, Sheila points out that speeding drivers can easily lose control when hitting a speed bump.
Describe Method of Reasoning
Sheila counters the position held by Robert. She does this by showing Robert’s solution to a given problem could produce undesirable consequences.
A
raises the objection that the problem with which Robert is concerned may not be as serious as he takes it to be
Sheila does not deny the seriousness of the problem Robert is addressing. Instead, she is showing that Robert’s solution could create more problems.
B
argues that the solution Robert advocates is likely to have undesirable side effects of its own
The solution Robert advocates for is installing speed bumps on certain streets. The undesirable effect Sheila points out is speeding drivers losing control of their vehicles when driving over speed bumps.
C
defends an alternative course of action as more desirable than the one advocated by Robert
Sheila does not defend a solution different from the one Robert proposes. She only addresses Robert’s proposed solution and argues that his solution also has the potential to be dangerous.
D
concedes that the solution advocated by Robert would be effective, but insists that the reasons for this are not those given by Robert
Sheila does not concede that Robert’s solution would be effective. In fact, it is implied she thinks Robert’s solution would be ineffective if speeding drivers were to hit speed bumps.
E
charges that Robert’s proposal would have no net effect on the problem he describes
Sheila does not claim that Robert’s proposal would have no effect on the problem. In fact, she thinks Robert’s proposal would have an adverse effect on the problem.
Summarize Argument: Phenomenon-Hypothesis
Historians hypothesize that the decline in Mesopotamian wheat production was caused by too much irrigation, too little drainage, and a subsequent buildup of salt in soil. No evidence is provided.
Notable Assumptions
The historians assume that wheat production decreases when salt accumulates in the soil, while barley production isn’t affected by (or benefits from) salt accumulation.
A
The cultivation of barley requires considerably less water than does the cultivation of wheat.
The Mesopotamians didn’t seem to be running out of water. They still could’ve grown crops that required lots of water.
B
Barley has much greater resistance to the presence of salt in soil than does wheat.
Wheat couldn’t be grown in the salt-laden soil, so Mesopotamians switched to a crop that could be grown in salt-laden soil: barley.
C
Prior to 2900 B.C., barley was cultivated along with wheat, but the amount of barley produced was far less than the amount of wheat produced.
We care about how much production increased and decreased. We’re not interested in raw totals.
D
Around 2900 B.C., a series of wheat blights occurred, destroying much of the wheat crop year after year.
This actually weakens the author’s argument. Wheat production didn’t decrease because of the accumulation of salt in the soil, but rather because of the constant blights.
E
Literary and archaeological evidence indicates that in the period following 2900 B.C., barley became the principal grain in the diet of most of the inhabitants of Mesopotamia.
The historians argue about why such a change happened. We don’t care if barley virtually superseded wheat in Mesopotamian diets.
Galina: It must be something other than sugar, because the concentration of sugar in the maple sap is so low that a squirrel would need to drink an enormous amount of sap to get any significant amount of sugar.
Summarize Argument
Galina disagrees with Lydia’s conclusion that red squirrels make holes in sugar maple trees in order to get the sugar in the trees’ sap. Galina concludes instead that the red squirrels are after something other than sugar. As support for this claim, Galina says that the concentration of sugar in the sap is so low that the squirrels would have to drink a very high amount of sap just to get a bit of sugar.
Notable Assumptions
Galina assumes that the red squirrels do not benefit from an insignificant amount of sugar. Galina also assumes that the red squirrels consume the sap by drinking it directly.
A
Squirrels are known to like foods that have a high concentration of sugar.
Squirrels’ preferences for other foods are irrelevant to the argument. Lydia and Galina are discussing squirrels’ motivations for consuming tree sap––we know that the squirrels consume the sap; Galina and Lydia just disagree about if they’re eating the sap to get the sugar.
B
Once a hole in a sugar maple trunk has provided one red squirrel with sap, other red squirrels will make additional holes in its trunk.
The topic of the argument is squirrels’ motivation for consuming sap. (B) just provides information about squirrels’ behavior patterns, but it does not say anything that could help determine whether squirrels are consuming the sap in order to get sugar, or for some other reason.
C
Trees other than sugar maples, whose sap contains a lower concentration of sugar than does sugar maple sap, are less frequently tapped by red squirrels.
Information about sugar concentrations in other trees is irrelevant. The arguments discuss squirrels’ motivation for consuming sugar maple tree sap; we don’t care about other trees. We don’t know why the squirrels are avoiding the other trees, and it’s the “why” that counts here.
D
Red squirrels leave the sugar maple sap that slowly oozes out of the holes in the tree’s trunk until much of the water in the sap has evaporated.
This weakens Galina’s argument because it shows that the squirrels are able to access the sugar in the sugar maple tree sap without drinking an enormous amount of sap. (D) makes it so that Galina’s premise does not provide support for her conclusion.
E
During the season when sap can be obtained from sugar maple trees, the weather often becomes cold enough to prevent sap from oozing out of the trees.
The arguments discuss squirrels’ reasons for consuming the sap. (E) tells us that accessing the sap may be difficult, but does not address squirrels’ motivations, so it does not weaken the argument.