sillyboy wrote:
I'm unable to decipher the argument. Please explain in simple terms.
Once one realizes that in option E, the pronoun "that" refers to "verification", then the question would be easier to comprehend.
Premise: In most computer-assisted proofs there are astronomically many types of instances to survey, and
no human being could review every step in the proof.
Conclusion: computer-assisted proofs involving astronomically many types of instances should not be accepted.
The basic link between the premise and conclusion is that human review (verification) is required in order to accept computer-assisted proofs. Option E states this assumption: it is not possible to verify (review by humans) the "extended verification of each step" (by the computer), i.e. the extended verification (by the computer) of each step is otherwise unverifiable (by humans).
(Note that in the phrase "for independent
verification of each step in a proof that is extended enough to be otherwise
unverifiable", "
verification" refers to verification by computers and "
unverifiable" refers to review by humans.)
Please post again if you still have doubts.