December 2004 LSAT Section 2 Question 2

Commentator: Many people argue that the release of chlorofluorocarbons into the atmosphere is harming humans by dam...

Paytonjd on March 19, 2023

Disproving a premise vs. weakening an argument

How is "Scientists have discovered that genetic changes occurred in our ancestors during the period in which the supernova affected Earth" not correct? It seems to me that this should weaken the argument most bc the argument says that a past supernova did NOT affect humans, but this answer says that it actually DID. If an answer choice disproves one of the premises that an argument is based on, doesn't that most seriously weaken the argument?

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Emil-Kunkin on March 23, 2023

Hi, generative changes are happening to humans all the time, this is simply evolution. E gives us no reason to think that these changes are in any way linked to the supernova. Moreover, we have to accept the premise that there were no significant effects from the supernova. This, even if these changes were directly caused by the supernova, they must not have been significant. This answer choice doesn't disprove the premise at all.

C is correct because it shows that the scenario 300,000 years ago is a bad analogy to today.