PrepTest 118, Section 3, Question 11
Biologist: Humans have five fingers because we descended(65 more words not shown)
Which one of the following,(7 more words not shown)
- AEveryone is equally(7 more words not shown)
- BHumans are never(8 more words not shown)
- CHumans are always(8 more words not shown)
- DThe perceived usefulness(12 more words not shown)
- EAt least one(9 more words not shown)
Reading the argument
Just as useful doesn't automatically mean just as satisfying. Two things could do the same job while we still prefer one of them.
I can see why the biologist's conclusion feels plausible. Having six fingers sounds strange to someone used to five, but if humans had always had six, that might seem perfectly normal. Still, that is a possible explanation of why we'd be content, not something established by the argument. The stated evidence concerns usefulness; the conclusion concerns how we'd feel.
What we’re looking for
Let's accept the claim that six fingers could be just as useful as five. We don't need to resolve the evolutionary story or imagine every possible number of fingers. For the strengthen question, I'd look for a connection between equal usefulness and equal contentment. That would support the actual step the biologist makes.
Working the answers
- A
This compares different people's satisfaction with the hands they have now. We need to compare satisfaction with five fingers and satisfaction with the hypothetical six-finger arrangement. Everyone could be equally happy with the present arrangement while being less happy with another equally useful arrangement. A leaves that comparison unresolved.
- B
This concerns things with unequal usefulness. Our two arrangements are equally useful, so this rule doesn't tell us how people would feel about them. Don't pick it merely because it mentions the right two ideas. We need a rule that connects those ideas in the situation we're given.
- CCorrect
Equal usefulness now guarantees equal contentment. The passage gives us the first part: five and six fingers are equally useful. C lets us reach the conclusion that people would be equally content with them.
This is stronger than a slight improvement to the argument. It supplies the missing rule directly. That is fine on a strengthen question; an answer that fully connects the stated premise to the conclusion certainly supports it.
- D
This questions where our perception of usefulness comes from. Even if that perception were an illusion produced by prejudice, we would still need to know how usefulness relates to contentment. The argument already asks us to accept equal usefulness; D doesn't explain why that would produce equal satisfaction.
- E
The conclusion is about what would happen if our ancestors and our hands had been different. It doesn't assert that such a fish actually existed. Establishing a six-phalange fish's existence wouldn't show that we would be content with six fingers anyway. The missing connection is about satisfaction, not whether the hypothetical history actually occurred.
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