Last time, I shared a surprising insight I discovered only after teaching the LSAT for a while (so make sure to read that article first).
This time, I'm going to walk you through HOW to use this strategy on one of my favorite Logical Reasoning questions of all time:
--- the Rattlesnake Folktale question (PrepTest 30, Section 2, Question 22 - p60 in Next 10) ---
If you have this PrepTest, awesome!
If not, don't worry. I'll show you how to use this strategy whether you have the question in front of you or not.
We know this is a necessary assumption question because it says "which one of the following is an assumption the argument requires?"
The argument describes a folktale about determining a rattlesnake's age.
According to this folktale, you can tell a rattlesnake's age by counting the number of sections on its rattle. This is because the rattlesnake forms a new section on its rattle each time it molts.
The argument goes on to say the rattlesnake age folktale doesn't work - but only because rattle sections break off due to their brittleness. It then concludes that if the rattles were not so brittle, the folktale would be correct, and its method for determining a rattlesnake's age folktale would work fine.
The question then asks for a necessary assumption. The correct answer tells us that food availability does not affect the molting rate. If food availability did affect the molting rate, then you could have two rattlesnakes, one that's had a lot of food in its life, one that's had very little food in its life, and they'd appear to be different ages.
So....the claim that the rattles' brittleness is the ONLY thing stopping the rattlesnake age folktale from being valid is making a huge assumption!
They're assuming that literally nothing else also needs to be true in order for the rattlesnake age folktale to be valid, so the argument depends upon this assumption in order to be valid.
Now, let's see how to change this question into a bunch of other question types!
Must Be True
This answer choice could have also been the correct answer choice to a Must Be True question. It needs to be true that food availability doesn't affect the molting rate in order for the argument to be valid (more on LSAT Necessary Assumption and Must Be True questions).
Must Be False
Because this large assumption must be true in order for the argument to work, the negation of this answer choice (the denial of this assumption) cannot be true for the argument to be valid, so it must be false that food availability affects the molting rate.
Strengthen
The argument as it stands is not airtight, so it's possible to strengthen it. Again, it's claiming that all we need to do to make this rattlesnake age folktale work is remove brittleness as a factor. If we view the answer choices as providing new information ("Which one of the following, if true, would most strengthen the argument?"), what we previously viewed as a Must Be True can now be viewed as a strengthener.
The correct answer to what was originally a necessary assumption question also serves to strengthen the argument by dismissing the possibility that food availability affects the molting rate.
Of course, choice A also serves to strengthen the argument. In fact, it fully justifies the conclusion and serves as a sufficient assumption. It just didn't NEED to be true. (Click here for tips on LSAT Strengthen questions.)
WeakenAn answer choice that strengthens the argument often does so by dismissing potential problems, alternative causes, or alternative explanations.
This is the case with our strengtheners above. If we negate an answer choice that would strengthen the argument, we are then weakening the argument.
As such, the negation of these answer choices would serve to weaken the argument.
Meaning that if we learned that food availability did affect the molting rate, that would weaken the argument. In fact, it would destroy the argument entirely. Similarly, if we learned that rattlesnakes did not molt exactly once a year, that would weaken the argument --- but only a tiny bit. (Click here for tips on LSAT Weaken questions.)
Evaluate the Argument
This is when we take a major strengthener or weakener and phrase it as a question or as a "what if?".
Question: Which one of the following would be most important to know in evaluating the conclusion drawn above?
Answer: Whether food availability affects the molting rate
If food availability affected the molting rate, that would weaken the argument.
If food availability did not affect the molting rate, that would strengthen the argument.
Resolve the Paradox / Discrepancy
Let's rephrase the stimulus by keeping the evidence the same but saying the conclusion did not logically follow. Something like:
"We genetically engineered rattlesnakes to remove brittleness as a factor, yet our top-secret Pentagon-funded rattlesnake age folktale still didn't reliably determine a rattlesnake's age."
How is this possible?
Well, if we learned that food availability affected the molting rate, that would explain why the rattlesnake age folktale still wasn't working.
Now go through the exact same process with another Logical Reasoning question. Doesn't matter which one - pick any LSAT PrepTest.
Then reach out and share what you did - I'd love to see what you come up with!
-Steve
Recommended Resources:
1. LSAT Courses
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2. Logical Reasoning Explanations
The explanations that should have come with the LSAT. These don't just fall back on "out of scope," but actually tell you why the wrong answers are wrong, why the right answers are right, and the easiest way to get the correct answer.
3. Logical Reasoning Cheat Sheet
Based on what I'd typically do in college: read what the professor emphasized and condense it all onto a single piece of paper. It gave me a quick reference, making things a lot less threatening and a lot more manageable.
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