PrepTest 110, Section 3, Question 11
The present goal of the field of medicine(88 more words not shown)
The argument above is based(7 more words not shown)
- ADegenerative brain disorders(7 more words not shown)
- BIt is still(18 more words not shown)
- CThere are degenerative(10 more words not shown)
- DDegenerative brain disorders(13 more words not shown)
- EMore is being(12 more words not shown)
Reading the argument
Living longer isn't the same as living forever. A transplant might add ten years to someone's life without making that life indefinite. So let's be careful about what the medical advances actually establish.
I'm also not sure the number of nerves proves that brain transplants will never be possible. Complicated isn't the same as impossible. Saying the moon is very far away wouldn't, by itself, prove that nobody could get there.
Still, suppose brain transplants really are impossible. The author predicts that as other transplants help people live longer, people with degenerative brain disorders will make up a larger and larger share of the population. I can see the picture: people survive problems with other organs but remain in the population with brain disorders.
What if those brain disorders cause people to die? Then we can't simply picture everyone with such a disorder accumulating indefinitely. We would need to understand what happens to these patients before assuming their share keeps rising.
What we’re looking for
The question asks for an assumption the argument relies on. My initial concern is that the author hasn't established the expected buildup of people with brain disorders. Let's look for something needed to connect the lack of brain transplants with that predicted result.
Working the answers
- A
The disorders don't have to start affecting younger people. They could keep appearing at the same ages while more people live long enough to reach those ages. The argument concerns the effect of extending life, not a change in the age at which brain disorders strike.
- B
We aren't told how many replacements of a particular organ someone might need. A person could receive one transplant or several, and we'd still have to address the author's claim about brain disorders. The argument doesn't require repeated transplants to be rare.
- CCorrect
This gives us a different way to question the predicted buildup. What if we could cure the disorders without replacing the brain? Imagine a pill that cured every degenerative brain disorder. The impossibility of brain transplants would no longer explain why those disorders should keep accumulating in the population.
The author needs at least some disorders that cannot be cured without a brain transplant. Otherwise, the missing transplant option wouldn't establish the claimed obstacle to curing them. C doesn't say every disorder requires a transplant, and it doesn't settle all our other questions about the population. It identifies a requirement of the reasoning the author gives.
- D
This may look close to my initial concern about patients dying, but it doesn't have to be true. The share of all deaths caused by brain disorders could be large or small while the share of people living with those disorders rises. We haven't been given a reason the current death share must be very small. D adds a specific comparison the argument doesn't require.
- E
Research spending doesn't tell us which treatments will succeed. Brain-disorder research could receive more funding or less funding than transplant research, and we'd still need to know whether disorders can be cured. The argument doesn't rely on this particular funding comparison.
More Necessary Assumption questions
Learn the LSAT our way
Our platform drills Necessary Assumption questions at your level and adjusts as you improve.