PrepTest 107, Section 3, Question 1
Braille is a method of producing text by(71 more words not shown)
Which one of the following(8 more words not shown)
- ABraille is the(15 more words not shown)
- BOnly people who(23 more words not shown)
- CPeople with the(19 more words not shown)
- DSome symbol systems(17 more words not shown)
- EEventually it will(19 more words not shown)
Reading the argument
Can a finger tell the difference between these heated patterns? Recognizing a pattern of bumps and recognizing that pattern through temperature are two different tasks.
I understand why keeping the same symbols could help. Someone who already reads braille would not need to learn what each pattern means. But that only helps if the person can feel which pattern is on the screen. Imagine knowing the meaning of every symbol and still being unable to tell where one warm dot ends and another begins. The familiar symbol system would not solve that problem.
The author moves straight from “same symbols” to “easy adjustment.” We need to stop at the step in between: can people who distinguish raised dots also distinguish the corresponding heated patterns?
What we’re looking for
That's what I want from the necessary assumption. The argument needs these readers to have the ability to tell the thermal patterns apart. We don't have to claim that the two surfaces feel identical or that the new technology is perfect. But without the ability to distinguish its symbols, the promised easy adjustment falls apart.
Working the answers
- A
Other symbol systems could work on the screen too. Perhaps it could display ordinary letters or another set of symbols. That would not prevent braille readers from using it. We care whether this system works for them, not whether it is the only system the technology can accommodate.
- B
Why would someone lose the ability to use the screen just because they also read another way? A person could read both braille and printed text. The conclusion includes anyone accustomed to braille, while B restricts the new system to people who rely on braille alone. That restriction is unnecessary.
- CCorrect
People who can distinguish braille symbols must also be able to distinguish similar patterns on the heated surface. This addresses the change that worried us: raised dots have become warm spots. If braille readers could not tell those thermal patterns apart, knowing the symbols would not let them easily use the device.
- D
This describes how some other symbol systems represent letters. A raised outline of an A and a pattern of dots standing for A could encode the same letter differently. Neither tells us whether a braille reader can distinguish heat patterns. The argument does not need this claim about other systems.
- E
Teaching someone braille through the new screen is a different project. The argument starts with people who already read braille and predicts that they can adjust to the screen. That could be true even if starting with the screen were a poor way to teach braille. We do not need the training process to work in the opposite order.
More Necessary Assumption questions
Learn the LSAT our way
Our platform drills Necessary Assumption questions at your level and adjusts as you improve.