September 2009 LSAT Section 5 Question 15

# Proofs relying crucially on computers provide less certainty than do proofs not requiring computers. Human cognition ...

4 Replies

Mehran on March 18, 2017

@ariella (C) is incorrect because we do not know that "whenever a computer replaces human calculation in a proof, the degree of certainty provided by the proof is reduced.""Whenever" is far too broad. We know that "proofs relying crucially on computers provide less certainty than do proofs not requiring computers."

(E) is also incorrect because it is far too broad to be supported by the information in the stimulus. This stimulus is about proofs relying crucially on computers.

There is nothing in the passage that supports the statement that "it is impossible to supplement the cognitive abilities of humans by means of artificial devices such as computers."

Remember, these are Must Be True questions so the answer choice must be 100% supported by the information in the stimulus.

Hope this helps! Please let us know if you have any other questions.

Jaimee on August 15 at 03:48AM

Could you clarify a bit more? I chose E but I'm still a bit fuzzy why B is correct.Shiyi on February 5 at 09:42PM

Why is B correct?Ravi on February 6 at 12:13AM

@Jaimee-Salgado and @Shiyi-Zhang,Happy to help!

In the stimulus, we're told that proofs that require using computers

(such as verifying the billionth decimal digit of pi) provide humans

with less certainty than proofs that don't require using computers do

(such basic arithmetic). And in cases such as basic arithmetic, people

often use computers as a convenient way to verifyâ€”not supplementâ€”human

cognition.

This is a really confusing stimulus, but once we have a handle on it,

we know that the author's arguing that proofs that require using

computers will always have a smaller degree of certainty because the

steps that are done by computers can never be verified by humans. In

stating this, the author reveals that she doesn't trust the degree of

verifiability of the proofs that require computers.

The question stem asks, "The statements above, if true, most strongly

support which one of the following?"

We're looking for something that can be strongly supported by what

we've been told in the stimulus.

(B) states, "We can never be completely sure that proofs relying

crucially on computers do not contain errors that humans do not

detect."

(B) deals with proofs that rely crucially on computers and says that

we'll never be certain that these proofs don't contain errors that

humans don't detect. This is perfectly consistent with the contents of

the stimulus because the gist of the stimulus is that proofs that rely

on computers can't be verified by humans, and therefore have less

certainty. It stands to reason from that that we would never be sure

that these types of proofs don't contain errors that we humans aren't

detecting because if humans can't verify the proof, then it's

certainly possible that humans could also not detect errors in the

proof.

Does this make sense? Let us know if you have any more questions!