Conditional Reasoning; Relation to Premises and Conclusions?

terrynicholasj

Hello Folks,

I posted this in the powerscore forum as well, but it looks a little dead over there. I was hoping I might be able to pick someone's brain about a particular question.

Hello everyone,

I'm working on conditional reasoning. Overall, I find using my intuition works 80% of the time, but sometimes I'm going to need to use the techniques discuss in Powerscore Logical Reasoning Bible Chapter 6 in order to maximize my score.

So, my question stems from question 2 of chapter 6 on page 171. The question is:

Admin Edit: Please don't post LSAT materials. LSAC owns a copyright on this and posting is a violation of the copyright. For reference, I believe this is from PT 31 Section 3 Number 22.

So, when I use my intuition, I get answer E. But I am practicing my conditional reasoning, and I am not able to get that answer.

I managed to get the following:

NEOR: Nucleomorph is the remains of an engulfed organism's nucleus
SVG: Single version of the gene
(I use slashed /// in order to designate "not")

/NEOR ------> SVG
and the contrapositive
/SVG -------> NEOR

Which, in the book is generally correct. However, the book then suggests that because:

Premise 1: /NEOR --------> SVG (I understand this as noted above)
Premise 2: /SVG
Conclusion: NEOR

And then somehow, to my bafflment, they come up with the statement that:

SVG ------> /NEOR (This is neither the contrapositive or the replication of the original conditional reasoning as it appears in the last sentence. In fact, it simply looks like a Mistaken Reveral to me.)

I am NOT understanding how they build this conditional reasoning argument. Indeed, my only clue is that maybe a premise=sufficient condition and that a conclusion=necessary condition that maybe this is how they ended up doing it? But my searches online don't show this to be true.

Additionally, answer choice E does not have any conditional indicators, making it difficult to decide what is the necessary and sufficient condition for choosing your answer. Are there any resources out there that help with doing this? Could I ask anyone for a little help? Thanks a tonne!!!

akistotle

PT31.S3.Q22 is a Most Strongly Supported question.
https://7sage.com/lsat_explanations/lsat-31-section-3-question-22/
[chlorarachniophytes]
/(remains of an engulfed organism’s nucleus) —> find only single version of the gene
/(find only single version of the gene)
————
remains of an engulfed organism’s nucleus = endosymbiosis

(E): chlorarachniophytes: remains of an engulfed organism’s nucleus = endosymbiosis

@terrynicholasj said:
And then somehow, to my bafflment, they come up with the statement that:
SVG ------> /NEOR (This is neither the contrapositive or the replication of the original conditional reasoning as it appears in the last sentence. In fact, it simply looks like a Mistaken Reveral to me.)

I don't see where they have "come up with this statement." I don't really get what you mean by this. Could you maybe elaborate on this? (E) is well supported by the stimulus.

Additionally, answer choice E does not have any conditional indicators, making it difficult to decide what is the necessary and sufficient condition for choosing your answer.

(E) just says chlorarachniophytes are remains of engulfed organism’s nucleus. I'm sorry but I don't know what you mean by "what is the necessary and sufficient condition for choosing your answer." (E) is not a conditional statement.

akistotle

I don't know which edition of PowerScore Bible you use, but I looked at my PowerScore Bible, which is the 2015 edition, and they seemed to have misprinted the conditional relationship in the 2015 edition on the page 173:
https://forum.powerscore.com/lsat/viewtopic.php?f=13&t=6993&p=17700
https://forum.powerscore.com/lsat/viewtopic.php?t=7148&p=18237&hilit=173#p18237

These posts may be able to answer your question.

terrynicholasj

You guys are awesome, thanks. Yes it turns out that it was a missprint....

akistotle

Glad it helped!