Some of my notes on LSAT LR arguments

User avatar
MS415
Posts: 48
Joined: Mon Dec 03, 2012 3:02 pm

Some of my notes on LSAT LR arguments

Postby MS415 » Mon Jan 07, 2013 3:00 pm

These are some of my personal notes on how to think about some of
The aspects of LSAT LR arguments. Hope it helps others while I am also seeking critiques and input.

1. When you assume something, you leave out info that might damage the argument if negated (falsified).
2. If you have not left out anything in the argument, you have not assumed anything ( but this seems impossible).
3. If you have a justified argument, it means that the argument's premises are enough to bring us to conclusion. But! It does not mean the argument contains no assumptions.
4. If you have falsified an assumption, you have weakened an argument.
5. If you have not weakened an argument, then you have not falsified an assumption.
6. If an assumption is not harmful and not neutral to the argument, it can be used to strengthen it.
7. If you cannot strengthen an argument, then all you have are harmful or biased ( not neutral) assumption(s).

03152016
Posts: 9189
Joined: Wed Dec 21, 2011 3:14 am

Re: Some of my notes on LSAT LR arguments

Postby 03152016 » Mon Jan 07, 2013 3:17 pm

.
Last edited by 03152016 on Tue Mar 15, 2016 3:20 am, edited 1 time in total.

User avatar
MS415
Posts: 48
Joined: Mon Dec 03, 2012 3:02 pm

Re: Some of my notes on LSAT LR arguments

Postby MS415 » Mon Jan 07, 2013 3:26 pm

Max324 wrote:
MS415 wrote:These are some of my personal notes on how to think about some of
The aspects of LSAT LR arguments. Hope it helps others while I am also seeking critiques and input.

1. When you assume something, you leave out info that might damage the argument if negated (falsified).
2. If you have not left out anything in the argument, you have not assumed anything ( but this seems impossible).
3. If you have a justified argument, it means that the argument's premises are enough to bring us to conclusion. But! It does not mean the argument contains no assumptions.
4. If you have falsified an assumption, you have weakened an argument.
5. If you have not weakened an argument, then you have not falsified an assumption.
6. If an assumption is not harmful and not neutral to the argument, it can be used to strengthen it.
7. If you cannot strengthen an argument, then all you have are harmful or biased ( not neutral) assumption(s).

The negation technique applies to necessary assumption questions only. I think your approach to assumptions is a little convoluted, especially since we're not distinguishing between sufficient and necessary assumptions. Here's something I wrote back in my prep days, reposting here for anyone who hasn't seen:

A correct sufficient assumption answer triggers the conclusion, regardless of whether it links the premises (however, it's very, very rare that it won't link). Sufficient assumption answers do not need to be true.

Example 1:
I ate bacon. Therefore I became fat.
Sufficient assumption: The high calorie count of bacon causes people who eat it to become fat.
Does it link? Yes. It links the consumption of bacon with becoming fat.
Does this need to be true? No. Suppose that the high calorie count of bacon does not cause people who eat it to become fat. I can still justify the conclusion if, say, bacon contains enzymes that slows down metabolism, resulting in weight gain.

Example 2:
All carnivores eat bacon. Therefore, Jason eats bacon.
Sufficient assumption: All people who are not named Mark eat bacon.
Does it link? No. The carnivore aspect of the argument remains unaddressed.
Does this need to be true? No. Perhaps some people who are not named Mark do not eat bacon. That doesn't necessarily prevent Jason from eating bacon.

A correct necessary supporter assumption links the premises, and must be true.

Example:
I became fat. Therefore, I must have eaten bacon.
Necessary supporter assumption: Only if one has eaten bacon can one become fat.
Does it link? Yes. It links eating bacon and becoming fat.
Does it need to be true? Yes. Suppose that one can become fat even if they have not eaten bacon. I can no longer justify my conclusion that I must have eaten bacon.

A correct necessary defender assumption defends against a weakener, and must be true.

Example:
I became fat. The cause of this must have been the bacon I ate.
Necessary defender assumption: Bacon does not contain negative calories that cause people who eat it to lose weight.
Does it link? No.
Does it need to be true? Yes. If bacon does cause people to lose weight, my conclusion is undermined.

I agree. I did not distinguish between necessary and sufficient assumptions. But, I did not intend to say that the negation technique can be used for more than necessary assumption questions. Anyway, your explanation is helpful. It might have been helpful for me to have put that #3 is the only time I intended to talk about sufficient assumptions (relating to " justify type questions" according to the bible).
Last edited by MS415 on Mon Jan 07, 2013 3:31 pm, edited 1 time in total.

03152016
Posts: 9189
Joined: Wed Dec 21, 2011 3:14 am

Re: Some of my notes on LSAT LR arguments

Postby 03152016 » Mon Jan 07, 2013 3:27 pm

.
Last edited by 03152016 on Tue Mar 15, 2016 3:20 am, edited 1 time in total.

User avatar
MS415
Posts: 48
Joined: Mon Dec 03, 2012 3:02 pm

Re: Some of my notes on LSAT LR arguments

Postby MS415 » Mon Jan 07, 2013 3:46 pm

Max324 wrote:I want to make a few specific comments on what you wrote:

1. When you assume something, you leave out info that might damage the argument if negated (falsified).

-Negation technique is for necessary assumptions only. (edit: just saw your reply, I know you get it! Belaboring the point for the benefit of others)

2. If you have not left out anything in the argument, you have not assumed anything ( but this seems impossible).

-Not sure what you're getting at here. An argument in an assumption question might be perfectly sound, without a noticeable gap (see my defender assumption example).

3. If you have a justified argument, it means that the argument's premises are enough to bring us to conclusion. But! It does not mean the argument contains no assumptions.

-Think of it this way: a sufficient assumption justifies the conclusion. Sometimes the premises need a little push to get to the conclusion; a sufficient assumption answer can provide that push.

4. If you have falsified an assumption, you have weakened an argument.

-Negate a necessary assumption, weaken an argument.

5. If you have not weakened an argument, then you have not falsified an assumption.

-Basically the contrapositive, if the negated AC doesn't weaken, it's not the necessary assumption.

6. If an assumption is not harmful and not neutral to the argument, it can be used to strengthen it.

7. If you cannot strengthen an argument, then all you have are harmful or biased ( not neutral) assumption(s).

-Assumptions support arguments. A sufficient assumption does this by guaranteeing the conclusion. Necessary defenders defend against a weakener. Necessary supporters link premises. You'll never have a correct assumption that weakens the argument.

Remember, think of necessary and sufficient assumptions like their namesake.

A sufficient assumption is sort of like a sufficient condition to the conclusion (when taken in context). Think: if this sufficient condition occurs, my conclusion, in context, occurs.

A necessary assumption is sort of like a necessary condition to the conclusion. Think: if my conclusion occurs, then my necessary assumption occurs.

Make sense?

Regarding #2, it seems that you are right about the possibility that a defender assumption could exist. But! doesn't the mere existence of a defender assumption entail that we have left out a possibility yet to be verified? Thus, we have left out something. I know this is also belaboring the point. But, my main concern is " if we have not left anything ( absolutely anything, which includes competing possibilities), then we have no assumptions.

It seems we agree on everything else. And your responses don't necessarily bring up any points of disagreement on the others.

03152016
Posts: 9189
Joined: Wed Dec 21, 2011 3:14 am

Re: Some of my notes on LSAT LR arguments

Postby 03152016 » Mon Jan 07, 2013 4:08 pm

.
Last edited by 03152016 on Tue Mar 15, 2016 3:20 am, edited 1 time in total.

User avatar
MS415
Posts: 48
Joined: Mon Dec 03, 2012 3:02 pm

Re: Some of my notes on LSAT LR arguments

Postby MS415 » Mon Jan 07, 2013 4:26 pm

Max324 wrote:
MS415 wrote:
Max324 wrote:I want to make a few specific comments on what you wrote:

1. When you assume something, you leave out info that might damage the argument if negated (falsified).

-Negation technique is for necessary assumptions only. (edit: just saw your reply, I know you get it! Belaboring the point for the benefit of others)

2. If you have not left out anything in the argument, you have not assumed anything ( but this seems impossible).

-Not sure what you're getting at here. An argument in an assumption question might be perfectly sound, without a noticeable gap (see my defender assumption example).

3. If you have a justified argument, it means that the argument's premises are enough to bring us to conclusion. But! It does not mean the argument contains no assumptions.

-Think of it this way: a sufficient assumption justifies the conclusion. Sometimes the premises need a little push to get to the conclusion; a sufficient assumption answer can provide that push.

4. If you have falsified an assumption, you have weakened an argument.

-Negate a necessary assumption, weaken an argument.

5. If you have not weakened an argument, then you have not falsified an assumption.

-Basically the contrapositive, if the negated AC doesn't weaken, it's not the necessary assumption.

6. If an assumption is not harmful and not neutral to the argument, it can be used to strengthen it.

7. If you cannot strengthen an argument, then all you have are harmful or biased ( not neutral) assumption(s).

-Assumptions support arguments. A sufficient assumption does this by guaranteeing the conclusion. Necessary defenders defend against a weakener. Necessary supporters link premises. You'll never have a correct assumption that weakens the argument.

Remember, think of necessary and sufficient assumptions like their namesake.

A sufficient assumption is sort of like a sufficient condition to the conclusion (when taken in context). Think: if this sufficient condition occurs, my conclusion, in context, occurs.

A necessary assumption is sort of like a necessary condition to the conclusion. Think: if my conclusion occurs, then my necessary assumption occurs.

Make sense?

Regarding #2, it seems that you are right about the possibility that a defender assumption could exist. But! doesn't the mere existence of a defender assumption entail that we have left out a possibility yet to be verified? Thus, we have left out something. I know this is also belaboring the point. But, my main concern is " if we have not left anything ( absolutely anything, which includes competing possibilities), then we have no assumptions.

It seems we agree on everything else. And your responses don't necessarily bring up any points of disagreement on the others.

Following that logic, every argument is leaving something out. If it helps you to process things that way, fine. Most people are going to take "leaving something out" of an argument to be referring to a "gap", meaning a disconnect between the premises and the conclusion; that's what I was assumed you were referring to.

Also, we do disagree on a few points; you might want to give it another read. Remember that there are no such things as helpful/neutral/harmful assumptions. Assumptions either ensure your conclusion, or are necessary for your conclusion; they won't harm an argument.



I think the bulk of our disagreements come from me being loose/creative with my phrasing of concepts.

For example:
1. I have brought up the term "helpful" and "hurtful" assumptions; for this, I meant regular necessary assumptions (because regular necessary assumptions always help the conclusion if established). For "hurtful" assumptions, I mean to bring up negated necessary assumptions.

2. neutral assumption is where you may have the greatest point. It seems laughable that there are neutral assumptions because we ask " if they have no role in helping or hurting the conclusion...what makes them a necessary assumption or an assumption to begin with? As you bring this up, I have to concede a flaw in my phrasing. But, not in my concept. What I was trying to refer to when I say "neutral" assumption is statements that neither help nor hurt the conclusion.

Let's take an argument for example.

P1: Jack is Hungry
Con: What I have in this box will help Jack


First, we have a necessary assumption/ helpful assumption, among other things, that the box is not empty, not just filled with useless sand, or not filled with packaging peanuts.

Second, we have a sufficient assumption, among others, that what is in the box may be a sandwich, money to buy a sandwich, etc.

neutral assumption may be the box is cardboard, wooden, or metal.

Hurtful assumption may be the box is filled with hunger pills ( to make him more hungry) sorry I got creative here, etc.


Finally, yes. you are right. Following the logic I have used to conclude that we are leaving something out if we have competing possibilities, then we seem to always be leaving somehthing out no matter what we argue. This is the very reason why I claimed in the original #2 note that we cannot have arguments without assumptions because "this seems impossible"




Return to “LSAT Prep and Discussion Forum”

Who is online

Users browsing this forum: Instrumental, ltowns1, MethodMan and 3 guests