LSAT 127 | Section 1 | Logical Reasoning: Q14

LR Question 14 Explanation

QUESTION TEXT: Over 90 percent of the human brain currently serves no purpose…

QUESTION TYPE: Flawed Reasoning

CONCLUSION: Over 90% of our brains serve no purpose, and we will be able to tap into this resource to achieve the insurmountable.

REASONING: The only evidence given is that many people with significant brain damage suffer no discernible ill effects.

ANALYSIS: The argument doesn’t give us any evidence that these unused parts of our brains are valuable. It just assumes we can use these sections of our brains for innovation. Perhaps these sections of the brain are used precisely because they aren’t that useful.

Sidenote: This LSAT question is based on a myth. It is not true that we fail to use 90% of our brains. We use 100% of our brains. The myth that we don’t comes from 19th century advertisement and noted fraud Uri Geller.

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1. I was tempted by this, but it doesn’t presume that the effects are easily discernible. It merely presumes that they would be discernible. Subtle difference. Also, they only make the claim about “many” victims of brain damage, not all victims.
2. The argument doesn’t presume that this is the only reason. It says “many” problems will be solved, not “any” problem.
3. No. It presumes they aren’t doing anything because massive brain damage doesn’t seem to impair brain functioning. That’s different from merely professing ignorance about what the brain does.
4. The argument doesn’t claim that we will actually solve the problems; it only claims that they “will be within our ability to solve.”
5. CORRECT. Yes. Though we may not be using the rest of our brains, it’s not clear what we could do with them if we could use them. The argument presumes that they would allow us to innovate, but it gives no evidence for this belief.

Recap: The question begins with “Over 90 percent of the human brain currently serves no purpose”. It is a Flawed Reasoning question. Learn more about LSAT Flaw questions in our guide to LSAT Logical Reasoning question types.