June 2020 LSAT Section 2 Question 20

The study of primates is interesting for many reasons, including the fact that only primates have opposable thumbs. T...

aligarman on June 15, 2022

No explanation for this question

Would you be able to diagram this to show how you reached this answwer? I diagrammed it and it seems that A logically follows from my diagram

Create a free account to read and take part in forum discussions.

Already have an account? log in

Emil-Kunkin on June 18, 2022

Hi Ali,

I'll take a shot at diagramming it- although this might look more like a restatement of the set of facts.

If opposable thumbs -> primate
Lemur =lower
If primate on Madagascar -> Lemur
If living lower and diurnal -> lemur
If higher -> evolved from diurnal lower

This is a lot of complex statements- most of them have more going on than a simple "if x then y."

Regarding (A), we know that the chimp evolved from a lower diurnal primate. However, we cannot say that that primate was a lemur. While we know that lemurs are the only living lower diurnal primates, it is possible that there were other ones in the past that were not lemurs.

We can prove B is correct since we know that lemurs are the only primates on Madagascar, so there cannot be any higher primates indigenous to Madagascar.