Conditional Reasoning LRBW Drill

[kan1dice]

Hello, I'm studying for the LSAT and I though that I had a pretty good grasp on Conditional Reasoning. It does not seem very difficult, yet I've discovered recently (last night) after picking up the Logical Reasoning Bible workbook that I seem to experience confusion with certain problems. The workbook gave an alternative way to phrase the question but I do not understand why it does not conform to The Unless Equation. Perhaps it's just me, would you mind explaining it to me please.

Conditional Reasoning Diagramming Drill

15. No one without sufficient exposure to linear algebra can enroll in this seminar.

I thought that w/o modifies the "enroll in this seminar" and I would need to negate the "no one" for the sufficient condition but that is incorrect. The diagram keeps the negation by slashing a line through "sufficient algebra exposure" and negates "enroll," so... confusion party of one here. Help please.

[Adam Tyson]

Hey Kandice, good question, and a challenging conditional statement there that combines "no one" and "without". I'd say you have two good ways to approach it - 1) technically and 2) intuitively.

A technical approach using the PowerScore method requires you to use the Unless Equation, as you stated. "Without", a special Necessary Condition indicator, is tied directly to "sufficient exposure to linear algebra", so S(ufficient) E(xposure) is your Necessary Condition. Now, what's left? "No one...can enroll in this seminar". Since the Unless Equation requires you to negate the stuff that isn't the Necessary Condition in order to reveal the Sufficient Condition, take that and turn it into "Someone can enroll in this seminar" - shorten that to just E(nroll) and that's now the Sufficient. Your diagram now reads E --> SE (if Enroll then Sufficient Exposure).

An intuitive approach would be where you take the statement as written and paraphrase it in a simpler if-then form. What are they really saying? They are saying you can't enroll without the prerequisite exposure, the right background. If you don't have that, you can't enroll. Now you have two much easier statements to deal with - my first one also uses the Unless Equation, my second states the Contrapositive, which is logically the same. I would probably diagram the Contra as SE --> E (those are supposed to be struck through, but to me they look more like they are underlined, so just trust me that they are negatives).

It seems that where you went wrong was in tying Without to the condition of enrolling. Sometimes the indicator words are not right next to the conditions they are modifying, but most of the time they are right there. Don't overcomplicate it. Use both approaches - a technical approach backstopped by your own intuition about what it really means - to avoid those errors, and you should be good to go.

I hope that helps!

[kan1dice]

Thank you.