Logical reasoning PrepTest 123 · Section 3 · Question 25

Flawed

Errors in Reasoning Questions / Sufficient & Necessary Questions

Anthropologists: not Evolved to cope in diverse environments → not Survive

Aa: Evolved to cope in diverse environments AND not Survive

Therefore, the Anthropologists are wrong.

There's a lot of complicated, Latin-y language in this stimulus, but there's also a conditional rule, so we should focus on that instead of how to pronounce Australopithecus (which we'll refer to as Aa).

In this argument, Aa is used as a counterexample to disprove the Anthropologists' viewpoint. What is that viewpoint? That had humans not evolved an ability, they wouldn't have survived. In other words, survival required the evolution of the ability to cope in various environments.

What would disprove that relationship? If someone believes that survival requires an ability, then a counterexample would be something that survived despite not developing the ability. Instead, the example of Aa is a species that didn't survive despite having the ability. That doesn't serve as a counterexample, because the view of the anthropologists is that the ability to cope in diverse environments was necessary to survival, not sufficient for it!

If, instead, the Anthropologists had said that any species that developed the ability to cope in diverse environments would survive, then the Aa example would disprove it. The argument here confuses the Anthropologists' sufficient and necessary conditions.