Summarize Argument
The author concludes that it’s likely Tom is an extreme insomniac. This is based on the fact that 90 percent of extreme insomniacs drink lots of coffee, and Tom drinks lots of coffee.
Identify and Describe Flaw
The author misinterprets the claim “Most A are B” as “Most B are A.” Although 90 percent of extreme insomniacs drink lots of coffee, that doesn’t tell us anything about what proportion of lots-of-coffee drinkers are extreme insomniacs. It could be that the vast majority of lots-of-coffee drinkers aren’t extreme insomniacs, even if most extreme insomniacs drink lots of coffee.
A
It fails to acknowledge the possibility that Tom is among the 10 percent of people who drink large amounts of coffee who are not extreme insomniacs.
The premises don’t establish that only 10 percent of people who drink lots of coffee are not extreme insomniacs. Also, the conclusion doesn’t say that Tom definitely is an extreme insomniac. So, the author acknowledges that he might not be an extreme insomniac.
B
It fails to consider the possible contribution to extreme insomnia of other causes of insomnia besides coffee.
The author’s argument does not make any assumptions about cause. The issue is whether membership in the set of people who drink lots of coffee implies a likelihood of membership in the set of people who are extreme insomniacs.
C
It relies on evidence that does not indicate the frequency of extreme insomnia among people who drink large amounts of coffee.
The author relies on the fact that 90% of extreme insomniacs drink lots of coffee. This does not reveal the frequency (i.e. proportion) of extreme insomnia among people who drink lots of coffee. It could be that only a small % of lots-of-coffee drinkers have extreme insomnia.
D
It draws an inference about one specific individual from evidence that describes only the characteristics of a class of individuals.
The author does not commit the whole-to-part fallacy. The issue is misinterpretation of the claim “90% of extreme insomniacs consume lots of coffee.” This statistic is not a claim about a class — it’s a claim about 90% of the individuals within the class.
E
It presumes without warrant that drinking coffee always causes insomnia.
The author doesn’t make any assumptions about cause. The issue is whether membership in the set of people who drink lots of coffee implies a likelihood of membership in the set of people who are extreme insomniacs.
Summarize Argument: Phenomenon-Hypothesis
The author presents the hypothesis that garbage dumps don’t harm wildlife. This hypothesis is supported by observations of baboons in the Masai-Mara game reserve : baboons who scavenge in the reserve’s garbage dumps grow faster and have more offspring than baboons who don’t eat garbage.
Notable Assumptions
The author assumes that eating garbage is not causing other harms to the baboons who scavenge in dumps. In other words, the author assumes that growth speed and number of offspring accurately represent the baboons’ health.
The author also assumes that there’s no alternative explanation for the differences between the baboons who eat garbage and the baboons who do not.
Finally, the author assumes that, even if the Masai-Mara baboons aren’t harmed by garbage, observations of these baboons can support a conclusion about wildlife in general.
The author also assumes that there’s no alternative explanation for the differences between the baboons who eat garbage and the baboons who do not.
Finally, the author assumes that, even if the Masai-Mara baboons aren’t harmed by garbage, observations of these baboons can support a conclusion about wildlife in general.
A
The baboons that feed on the garbage dump are of a different species from those that do not.
This weakens the argument, because it proposes an alternative explanation for the differences between the scavenging and non-scavenging baboons. If we can’t accurately compare the impact of garbage between these groups, the argument is weakened.
B
The life expectancy of baboons that eat garbage is significantly lower than that of baboons that do not eat garbage.
Like (C) and (E), this weakens the argument by adding a new way that eating garbage could harm the baboons’ health. If the scavenging baboons grow faster and have more offspring, but also die faster, it becomes much harder to say that garbage does not harm them.
C
The cholesterol level of garbage-eating baboons is dangerously higher than that of baboons that do not eat garbage.
Like (B) and (E), this weakens the argument by giving us another example of how garbage could be harming the baboons. This rebuts the author’s assumption that growth speed and birth rates are the only relevant markers of the baboons’ health, thus weakening.
D
The population of hyenas that live near unregulated garbage landfills north of the reserve has doubled in the last two years.
This does not weaken the argument. If these garbage dumps are helping the hyena population grow, that may even strengthen by demonstrating another species that isn’t harmed. Even if not, this doesn’t give us any reason to doubt the argument, so does not weaken.
E
The rate of birth defects for the baboon population on the reserve has doubled since the first landfills were opened.
Like (B) and (C), this weakens the argument by demonstrating a harm possibly caused by the garbage dumps that the author has overlooked. This harm isn’t just to the scavenging baboons, but the timing relative to the dumps opening suggests a possible causal link, thus weakening.
Summary
Chronic back pain is often caused by a damaged spinal disk. Usually, pain develops long after the damage occurs. To further this point, it is estimated that a significant number of people have a damaged disk but no chronic pain. For these people, pain usually develops due to muscle weakness caused by a lack of exercise.
Strongly Supported Conclusions
A lack of exercise can contribute to the onset of chronic back pain.
Exercise may play a role in preventing chronic back pain.
Many people have damaged disks, but do not experience chronic pain.
A damaged spinal disk does not necessarily mean one will experience chronic pain.
Exercise may play a role in preventing chronic back pain.
Many people have damaged disks, but do not experience chronic pain.
A damaged spinal disk does not necessarily mean one will experience chronic pain.
A
Four out of five people over the age of 30 can be sure they will never develop chronic back pain.
Unsupported. This is too strong to conclude this about the remaining 4/5. This group could develop chronic back pain from sources other than a damaged disk. They could also have a damaged disk that DOES show chronic symptoms.
B
People who exercise their abdominal and spinal muscles regularly are sure to be free from chronic back pain.
Unsupported. This only talks about chronic back pain caused by damaged disks - we can’t draw conclusions about all back pain. Additionally, we know that pain in certain cases is generally caused by weakened muscles - not all. We cannot be sure.
C
Patients rarely suffer even mild and fleeting back pain at the time that a spinal disk first becomes herniated or degenerated.
Unsupported. The stimulus discusses chronic pain symptoms. Chronic is prolonged - we cannot conclude from this about acute pain that may or may not occur at the time of injury.
D
Doctors can accurately predict which people who do not have chronic back pain will develop it in the future.
Unsupported. We know that not everyone that has a damaged disk will develop back pain. While a lack of exercise may play a role, there is no evidence to support a method for being able to accurately predict who will develop back pain.
E
There is a strategy that can be effective in delaying or preventing the onset of pain from a currently asymptomatic herniated or degenerated spinal disk.
Strongly supported. Exercise is a strategy can be effective for delaying or preventing the onset of pain by preventing the deterioration of the abdominal and spinal muscles in those with a damaged disk.