Recent studies indicate a correlation between damage to human chromosome number six and adult schizophrenia. We know, however, that there are people without damage to this chromosome who develop adult schizophrenia and that some people with damage to chromosome number six do not develop adult schizophrenia. So there is no causal connection between damage to human chromosome number six and adult schizophrenia.
Summarize Argument
The author concludes that there is no causal connection between damage to chromosome six and adult schizophrenia. He supports this by pointing out that some people with schizophrenia don't have damage to chromosome six, and some people with chromosome six damage don't develop schizophrenia.
Identify and Describe Flaw
The author cites studies that establish a correlation between chromosome six damage and schizophrenia and then concludes that the two aren’t causally connected. But just because there are some exceptions to the correlation doesn’t prove that there is no causal connection between chromosome six damage and schizophrenia at all.
For example, there is a causal relationship between smoking and lung cancer, but some smokers never get lung cancer while some non-smokers do get lung cancer.
A
The argument ignores the possibility that some but not all types of damage to chromosome number six lead to schizophrenia.
The author overlooks the possibility that not all kinds of damage to chromosome six cause schizophrenia. If some types of damage do lead to schizophrenia, then there could still be a causal connection between the two, even if they aren't always linked.
B
The argument presumes, without providing evidence, that schizophrenia is caused solely by chromosomal damage.
The argument actually assumes that schizophrenia is not caused by damage to chromosome six, simply because the two are not perfectly correlated.
C
The argument makes a generalization based on an unrepresentative sample population.
This is the cookie-cutter flaw of using unrepresentative samples. However, we have no reason to believe that the recent studies or the author’s argument are based on unrepresentative samples of people with chromosome 6 damage or schizophrenia.
D
The argument mistakes a cause for an effect.
The author doesn’t mistake a cause for an effect. Instead, he assumes that there is no causal connection between chromosome six damage and schizophrenia at all.
E
The argument presumes, without providing warrant, that correlation implies causation.
This is the cookie-cutter flaw of assuming that correlation implies causation. But the author concludes that there’s no causal connection at all. Instead of (E), he assumes, without providing warrant, that an imperfect correlation implies a lack of causation.
A
Most of the people who contract hepatitis E are young adults who were probably exposed to the virus in childhood also.
B
Some laboratory animals exposed to one strain of the hepatitis virus developed immunity to all strains of the virus.
C
Researchers developed a successful vaccine for another strain of hepatitis, hepatitis B, after first isolating the virus that causes it.
D
The virus that causes hepatitis E is very common in some areas, so the number of people exposed to that virus is likely to be quite high in those areas.
E
Many children who are exposed to viruses that cause childhood diseases such as chicken pox never develop those diseases.
Amar: Frankness is not intimacy. Intimacy requires a real social bond, and social bonds cannot be formed without direct personal contact.
A
barriers to self-revelation hinder the initial growth of intimacy
B
E-mail can increase intimacy between friends
C
intimacy between those who communicate with each other solely by e-mail is possible
D
real social bonds always lead to intimacy
E
the use of e-mail removes barriers to self-revelation
A
Since about ten years ago, the percentage of people who wear sunscreen every time they spend time in the sun has increased.
B
Most people whose skin is prematurely wrinkled have spent a large amount of time in the sun without wearing sunscreen.
C
The specific cause of premature skin wrinkling was not known until about ten years ago.
D
People who wear sunscreen now are less likely to become sunburned than were people who spent the same amount of time in the sun wearing sunscreen ten years ago.
E
Until about ten years ago, people who wore sunscreen were no less likely to have premature wrinkles than were people who spent the same amount of time in the sun without wearing sunscreen.
Frank: What you conclude is itself a general rule. If we assume that it is true, then there is at least one general rule that has no exceptions. Therefore, you must withdraw your conclusion.