Sufficient Assumption Questions

lsatstudier

Any advice for breaking down SA questions into valid argument forms like JY does in the videos? The more questions I see, the more challenging it is to find an AC that matches my diagram. Is there another way to approach SA questions? Sometimes it seems like the AC for these questions is just a restatement of the conclusion and/or my prephrases don't match the answer choices very well. Does anyone think of these questions like strengthen questions? Any suggestions would be great! Thank you!

Zachary_P

As tough as it may seem at first, I would really encourage trying to view sufficient assumption questions like JY does. This questions rise to the level of outright validity, so while another AC may indeed strengthen the argument, only one will make the argument completely valid. On some of the tougher SA questions, the difficult part is not the logic. With the valid argument forms in the CC, you should be able to solve upward of 90% of SA questions. This difficult part is parsing through tough grammar. For these questions, the conditional logic indicators will be hidden more than the simple "if... then..." format. The LSAT also likes to use negations (especially in terms of group 3 and 4 indicators). So my advice would be to master translations in the CC and memorize the argument forms. I've been studying for half a year now, and I still write out the lawgic on the tougher SA questions, and it makes all the difference being able to visualize what is going on.

To your point about the correct AC seeming like the conclusion, this is a good observation. It won't be the conclusion, of course, but for many many SA questions, the correct AC will link something in the premise to something in the conclusion. So continue to search for that link.

With prephrasing, know the contrapositive of your prephrase as well. The LSAT can hide an obvious answer choice with a flip and a negation to make things just a bit tougher from what the obvious prephrase might be.

Hope this helps!

TheMikey

look for an answer choice that is legit (if PREMISE ---> then CONC). Pick an AC that if placed between the supporting premise and the conclusion, it would let the conclusion make sense.

I see what you mean by the AC being a restatement of the conclusion, but almost always the correct AC will link the premise and conclusion! it won't merely be a restatement of the conclusion alone, though.

Cant Get Right

Here's a way to break these down that might be beneficial. I don't diagram anymore, but I think my intuitive process is something like this. I think it would make for a good exercise. If you can identify all these variables quickly and accurately, they always interact the same way.

Step One: Identify the variables.

Frequently, this is the real challenge of SA questions. They can make this incredibly difficult, and it's a task that I feel like is often overlooked as something that needs to be approached deliberately.

So let's say our variables are:
A --> B --> C
A
therefore
X

Step Two: Identify the trigger.

The trigger is the variable that is confirmed by the argument which sets the conditional chain into motion. A --> B --> C is largely meaningless. By providing the non-conditional A, they trigger the chain. A is the trigger. In some arguments, there is no trigger, and you will need to provide one in the AC. This argument would look something like:

A --> B --> C
therefore
C

Our answer would simply be A here.

Step Three: Identify the hanger.

If they're not just looking for a trigger, there's more to do. Once we know our variables, there will be one that is left hanging--a triggered live-wire that dead ends. This variable is frequently the sufficient variable in our AC with our conclusion in the necessary (although they could flip it, of course). In this chain, our hanger is C.

Step Four: Pair the hanger variable with the conclusion.

C --> X
or
/X --> /C

They do have a few variations they can use to complicate this, but they're pretty simple. The most common would be to have the conclusion represented as an untriggered conditional like:

A --> B --> C
A
therefore
D --> X

It's basically the same thing though. In Step Four, you pair your live hanger with the dead sufficient condition from the conclusion in order to charge it:

C --> D

Hope this helps. You don't want to rely on this or mapping either on the real thing, but they are good exercises in order to learn to see how it all fits together. Just remember to identify your variables at the beginning! That's normally the hard part!

BinghamtonDave

Excellent, excellent post by @"Cant Get Right"

LSATman1

Have you done the formal logic lessons? A conditional relationship (e.g. X-->Y) can be phrased in many different ways (e.g. If X then Y, All X are Y, Not X unless Y, etc.)

For some SA questions, the correct choice is often a conditional statement, but may be phrased differently from what you expect. It helps to be able to identify the different ways to phrase conditional statements and to know when a statement is logically equivalent to your predicted answer. Also, the correct answer may be the contrapositive of what you are looking for.

Mellow_Z

@"Cant Get Right" said:
Here's a way to break these down that might be beneficial. I don't diagram anymore, but I think my intuitive process is something like this. I think it would make for a good exercise. If you can identify all these variables quickly and accurately, they always interact the same way.

Step One: Identify the variables.

Frequently, this is the real challenge of SA questions. They can make this incredibly difficult, and it's a task that I feel like is often overlooked as something that needs to be approached deliberately.

So let's say our variables are:
A --> B --> C
A
therefore
X

Step Two: Identify the trigger.

The trigger is the variable that is confirmed by the argument which sets the conditional chain into motion. A --> B --> C is largely meaningless. By providing the non-conditional A, they trigger the chain. A is the trigger. In some arguments, there is no trigger, and you will need to provide one in the AC. This argument would look something like:

A --> B --> C
therefore
C

Our answer would simply be A here.

Step Three: Identify the hanger.

If they're not just looking for a trigger, there's more to do. Once we know our variables, there will be one that is left hanging--a triggered live-wire that dead ends. This variable is frequently the sufficient variable in our AC with our conclusion in the necessary (although they could flip it, of course). In this chain, our hanger is C.

Step Four: Pair the hanger variable with the conclusion.

C --> X
or
/X --> /C

They do have a few variations they can use to complicate this, but they're pretty simple. The most common would be to have the conclusion represented as an untriggered conditional like:

A --> B --> C
A
therefore
D --> X

It's basically the same thing though. In Step Four, you pair your live hanger with the dead sufficient condition from the conclusion in order to charge it:

C --> D

Hope this helps. You don't want to rely on this or mapping either on the real thing, but they are good exercises in order to learn to see how it all fits together. Just remember to identify your variables at the beginning! That's normally the hard part!

This is honestly one of the best pieces of advice I've come across in my LSAT journey so far. If anyone else is struggling with these question types - this is a perfect explanation on how to get through them.