Dumb Question

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brickman
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Dumb Question

Postby brickman » Fri Feb 04, 2011 7:23 pm

Just trying to get as thorough of an understanding as possible on the following, so any comments to that effect are appreciated.


So, given a premise and a conclusion in an informal argument, where the premise is reasonable grounds for the conclusion, but not sufficient grounds in the context of a formal argument, is the assumption of the argument that the premises are sufficient to necessitate the conclusion?

Ex:

Apples are delicious
Thus, I should eat apples.

Is the assumption of informal arguments like this that apples being delicious is sufficient?

Such that:

If it is valid that I should eat apples -> premise is sufficient.

and its contrapositive

if the premise is insufficient -> then not nec. valid that I should apples.


I'm just trying to understand assumptions on a broader level, and maybe it's unnecessary, but I just felt like it was worth thinking about.

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AreJay711
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Re: Dumb Question

Postby AreJay711 » Fri Feb 04, 2011 7:28 pm

Never assume anything that you aren't told. Maybe you are allergic to apples. Maybe apples are poisonous. Maybe there are only 3 apples left in the whole universe after a cataclysmic destruction of earth. OK so the last one is a stretch but still, don't assume anything.

mchuynh
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Re: Dumb Question

Postby mchuynh » Fri Feb 04, 2011 7:34 pm

I am not sure if this is what you're asking but you are assuming that just because apples are delicious, then you should eat it.

Something is missing- the argument is not connecting

Apples are delicious

you should eat delicious things <-- this is what you are assuming right now

you should eat apples.

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NZA
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Re: Dumb Question

Postby NZA » Fri Feb 04, 2011 7:35 pm

mchuynh wrote:I am not sure if this is what you're asking but you are assuming that just because apples are delicious, then you should eat it.

Something is missing- the argument is not connecting

Apples are delicious

you should eat delicious things <-- this is what you are assuming right now

you should eat apples.


+1

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TatteredDignity
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Re: Dumb Question

Postby TatteredDignity » Fri Feb 04, 2011 7:36 pm

brickman wrote:Ex:

Apples are delicious
Thus, I should eat apples.

Is the assumption of informal arguments like this that apples being delicious is sufficient?


Yes, sort of, but just to clarify, the "assumption" is also a premise, it's just an unstated one. In this case, that premise is "if something is delicious, it should be eaten." So there are two premises (one of which is unstated), and the conclusion.

I don't really like calling sufficient conditions "assumptions", as in the case above. I typically reserve that for necessary conditions. For example, you could reach the conclusion above validly by adding the premises "apples are fruits" and "fruits should be eaten" and then the delicious element is in there but playing no role.

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TatteredDignity
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Re: Dumb Question

Postby TatteredDignity » Fri Feb 04, 2011 7:38 pm

AreJay711 wrote:Never assume anything that you aren't told. Maybe you are allergic to apples. Maybe apples are poisonous. Maybe there are only 3 apples left in the whole universe after a cataclysmic destruction of earth. OK so the last one is a stretch but still, don't assume anything.


That is good advice, generally, but I don't think it's on point.

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Re: Dumb Question

Postby justadude55 » Fri Feb 04, 2011 7:39 pm

brickman wrote:Just trying to get as thorough of an understanding as possible on the following, so any comments to that effect are appreciated.


So, given a premise and a conclusion in an informal argument, where the premise is reasonable grounds for the conclusion, but not sufficient grounds in the context of a formal argument, is the assumption of the argument that the premises are sufficient to necessitate the conclusion?

Ex:

Apples are delicious
Thus, I should eat apples.

Is the assumption of informal arguments like this that apples being delicious is sufficient?

Such that:

If it is valid that I should eat apples -> premise is sufficient.

and its contrapositive

if the premise is insufficient -> then not nec. valid that I should apples.


I'm just trying to understand assumptions on a broader level, and maybe it's unnecessary, but I just felt like it was worth thinking about.

This is a good example.

You're assuming anything that's delicious should be eaten.

What if poison is delicious?.... or small children?

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NZA
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Re: Dumb Question

Postby NZA » Fri Feb 04, 2011 7:40 pm

0LNewbie wrote:
AreJay711 wrote:Never assume anything that you aren't told. Maybe you are allergic to apples. Maybe apples are poisonous. Maybe there are only 3 apples left in the whole universe after a cataclysmic destruction of earth. OK so the last one is a stretch but still, don't assume anything.


That is good advice, generally, but I don't think it's on point.


It is. He's pointing out that the conclusion cannot be drawn from a single premise.

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brickman
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Re: Dumb Question

Postby brickman » Sat Feb 05, 2011 12:51 am

I don't think I'm getting my point across.

I know that given a premise in an informal "argument" we can not conclude the conclusion to be valid. The only way we can really know that a conclusion is valid is through a syllogism.

So like:

Apples are delicious
If apples are delicious, then I will eat them.
I eat apples.

A
A->B
B

I get that, but that is not what I was trying to figure out.

What I'm trying to get at is if just had:

Apples are delicious
I eat apples

Informal arguments assume that their premises are sufficient (right?), that they think that given these premises the conclusion necessarily follows, they think (incorrectly) that the premise is sufficient to necessitate the validity of the conclusion.

This is the assumption, is it not?

That, necessarily, if I eat apples, the argument assumes that apples are delicious is sufficient grounds to make this conclusion.

Yet we know with all informal arguments, because they are not syllogistic in nature (and lack almost always formal logic components) are invalid, or at least can not be concluded to be definitively valid since the basis for them is not a tight relationship pattern that defines conditional statements and formal valid argument structures.

So the premises are insufficient, we know this. We know that just because apples are delicious that it is bullshit that just because we know this to be true that we should necessarily believe this is sufficient grounds to eat apples. I see this, I get it.

I know that since these arguments are informal and hence can not be assumed to have necessarily valid conclusions that I can come up with some reason why the premises may not be sufficient, but I can't quite put my finger on it.

for example:

Apples are delicious
I eat apples.

I know this is not valid argumentation, we are given a characteristic and conclude another characteristic and there is no relationship between the two, yet my mind immediately says "well duh this is bad, just b/c they are delicious they could be poisonous, so you don't wanna eat them", but I can't put my finger on how that statement relates to what I want to say

sorry, I dunno how to be more succinct.

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suspicious android
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Re: Dumb Question

Postby suspicious android » Sat Feb 05, 2011 2:17 am

brickman wrote:I know this is not valid argumentation, we are given a characteristic and conclude another characteristic and there is no relationship between the two, yet my mind immediately says "well duh this is bad, just b/c they are delicious they could be poisonous, so you don't wanna eat them", but I can't put my finger on how that statement relates to what I want to say

sorry, I dunno how to be more succinct.


Yeah, I don't think I have any idea what you're trying to ask now. Yeah, when you conclude something, you're making a claim that the truth of the premises given ensure the truth of the conclusion. Usually, the arguments are not airtight, because they rely on any number of unstated assumptions. There's no special name for this that I'm aware of, but you could say that your example argument is a non sequitur. That's just a fancy way of saying the conclusion doesn't follow from the premises, though. All logical fallacies are just special cases of a non sequitur.

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JazzOne
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Re: Dumb Question

Postby JazzOne » Sun Feb 06, 2011 3:13 am

OP:

I think there is a flaw in your conception of an assumption in the context of informal argumentation. I will use your example to illustrate the point:

Apples are delicious.
Therefore, I should eat apples.

Your articulation of the assumption is "the premise is sufficient to draw the conclusion." In our example, that would equate to "if apples are delicious, then I should eat apples." That is surely the easiest way to articulate the assumption, but it's almost tautological. Why is it that apples' being delicious is sufficient to conclude that I should eat them? What is the internal logic of the argument? What are its implicit terms? The assumption might be a bit broader than we have thus far articulated. Perhaps the assumption is "if something (anything at all) is delicious, then I should eat it." That formulation also seems consistent with the argument's logic. The bottom line is that we cannot discern the scope of the assumption because the argument has little structure. It's just two assertions, one of which is purported to justify the other. We can connect the two ideas in various ways, but doing so is a projection of the arguments we'd like to make rather than an interpretation of the argument that actually was made.

I think that is the fundamental problem with these overly simplistic examples. There was another thread on TLS that ran for many pages. The debate was entirely over a two-line argument and the assumption of that argument. There were a lot of really intelligent people who vehemently disagreed over the answer to that question, and there really was never a consensus on who was correct. I suspect that the problem was that there simply was no right answer. The argument was overly simplistic, and so it just didn't make sense to ask what the assumption was. There were some obvious ways to connect the premise to the conclusion in a syllogistic fashion, but the debate, if I understand it correctly, turned on the internal logic of the argument. It's impossible to ascertain the internal logic when the structure is reduced to a single premise and a conclusion. In such an overly simplistic argument, the only assumption that can be articulated with any adherence to the internal logic is "the premise is sufficient to draw the conclusion." I will refrain from posting that particular argument here because the chances of it derailing this thread are high. Anyone can PM me if you'd like to discuss a very interesting and fascinating logical puzzle that I believe I have solved.

Sorry for the wall of text. My basic point is that real arguments and real LSAT questions will not be so devoid of structure. The structure of actual informal arguments will allow you to state the assumption in more specific terms because the structure of the argument will suggest a particular way in which the omitted idea is connected to the stated ideas. That connection will be more subtle than just "this leads to that." I know that was a confusing response. I'll leave you with a specific example to make my point clearer. This is an elaboration of your argument:

Apples are delicious.
Delicious foods are likely to be nutritious.
Therefore, I should eat apples.

Now that I've provided some depth to the structure, the logic of the argument is clear. The scope of the assumption is obvious: "I should eat foods that are likely to be nutritious."
But the assumptions is NOT "the premises are sufficient to draw the conclusion" (i.e., "if apples are delicious and delicious foods are likely to be nutritious, then I should eat apples"). Stating the assumption in this way is basically just restating the argument as it was originally written. It doesn't reflect an understanding of the argument's internal logic.

Conclusion: Your definition of assumption is overly simplistic and only applies to the most basic of arguments. Arguments with more nuance will entail assumptions with more nuance.
Last edited by JazzOne on Sun Feb 06, 2011 4:23 pm, edited 4 times in total.

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EarlCat
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Re: Dumb Question

Postby EarlCat » Sun Feb 06, 2011 11:14 am

JazzOne wrote:My basic point is that real arguments and real LSAT questions will not be so devoid of structure.

We sometimes see simplistic arguments like OP's example in principle justify questions, which don't rely so heavily on analyzing structure. The answer in that case would just be a generalization along the lines of "One should eat delicious things."

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Re: Dumb Question

Postby JazzOne » Sun Feb 06, 2011 3:01 pm

EarlCat wrote:
JazzOne wrote:My basic point is that real arguments and real LSAT questions will not be so devoid of structure.

We sometimes see simplistic arguments like OP's example in principle justify questions, which don't rely so heavily on analyzing structure. The answer in that case would just be a generalization along the lines of "One should eat delicious things."

I can't think of any specific examples, but I agree that the structure of the argument is less important for that type of question.

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Re: Dumb Question

Postby brickman » Sun Feb 06, 2011 4:42 pm

Alright, let me try something else.

An example:

In making a decision as to whether or not to buy a house, all that the potential owner wants is a comprehensive report on neighborhood demographics. The realtor provides him with a packet of information detailing schools, parks, number of children/household, average annual income, and cultural attractions. The owner makes a decision on the house.

So making a decision requires a comprehensive report and he gets data from a realtor.

The conclusion assumes the validity that the decision was made on the basis of a comprehensive report. What's the premise...well, he got some data from the realtor. Are we saying that the assumption isn't that the data provided isn't sufficient to necessitate the validity of the conclusion?

It feels like the argument is assuming the realtors data is sufficient to say that it is a comprehensive report and thus that a decision can be made.

what am I missing here....

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Re: Dumb Question

Postby JazzOne » Sun Feb 06, 2011 5:16 pm

brickman wrote:Alright, let me try something else.

An example:

In making a decision as to whether or not to buy a house, all that the potential owner wants is a comprehensive report on neighborhood demographics. The realtor provides him with a packet of information detailing schools, parks, number of children/household, average annual income, and cultural attractions. The owner makes a decision on the house.

So making a decision requires a comprehensive report and he gets data from a realtor.

The conclusion assumes the validity that the decision was made on the basis of a comprehensive report. What's the premise...well, he got some data from the realtor. Are we saying that the assumption isn't that the data provided isn't sufficient to necessitate the validity of the conclusion?

It feels like the argument is assuming the realtors data is sufficient to say that it is a comprehensive report and thus that a decision can be made.

what am I missing here....

This is a tough example to analyze because the conclusion is implicit. There are several different conclusions we could draw from this argument.

For example, this argument may be intended to prove that the potential owner's desire for a comprehensive report was satisfied. If that's the conclusion, then the assumption is that the owner would not make a decision unless his desire was satisfied.

However, the argument could be intended to prove the stronger conclusion that the report is in fact a comprehensive report. In that case, the argument is making an additional assumption that the owner's desire would be satisfied only by objective truth.

Based on the penultimate sentence of your post, I assume you are construing the argument to defend the stronger conclusion. So, the report, in and of itself, is not sufficient to draw the conclusion, and the argument does not suggest that. Rather, the argument suggests that the combination of the report plus the other two premises is sufficient to draw the conclusion. Like I said in a previous post, the assumption is more nuanced than your articulation, and the assumption pertains to how the unstated ideas fit into the framework of the stated ideas. I suggest that the unstated premises (assumptions) fit into this particular argument as I outlined above.

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Re: Dumb Question

Postby Jeffort » Sun Feb 06, 2011 6:26 pm

Although interesting for philosophical discussion, I think this is straying away from the pragmatics of how to deal with assumptions as they relate to properly analyzing LSAT LR arguments to find the credited answer choice for each question type that involves an argument and assumptions.

OP: Are there particular LSAT question types or particular questions that you are having trouble with due to trying to determine what assumption(s) the presented argument makes? Putting this line of discussion into that context would be much more likely to be beneficial to improving your performance than a very abstract philosophical discussion about logic and assumptions.

In LSAT context, knowing the difference between what constitutes a sufficient assumption vs. a necessary assumption to an argument is really important when solving necessary assumption questions vs. sufficient assumption (AKA justify the conclusion) questions.

With sufficient assumption (justify the conclusion) questions the credited answer choice, when added to the supplied argument as an additional established premise results in having a deductively valid argument where the premises combined prove that the conclusion 100% must be true.

With necessary assumption questions the credited answer choice, when added as an established premise does not have to (and usually will not) make the argument deductively valid, but instead just establishes a premise that must be true in order for the supplied in the stimulus argument to be a decent inductive argument. In other words, if the premise stated in the credited answer choice is not true, then the argument as supplied in the stimulus majorly fails being a good inductive argument, hence the use of the denial/negation test/technique that prep classes and books teach you to use on this question type.

In terms of other types of assumptions important to the logic LSAT logical reasoning questions test and how it is tested in LSAT form, you have to assume that all stated premises provided in the stimulus (whether it be an argument or just a set of information) are true, regardless of whether or not any support is given for the particular statement.

When an LR stimulus (whether or not it is an argument) states something as being a fact in a premise, you have to accept that it is a true fact without having any support proving that it is. In essence, if a premise in the text says something is true (not the conclusion!), you have to assume that the statement is true and reason within that, even if the stated premise is factually false in the real world. Therefore, you are trusting and ASSUMING that the stated premises are actually true statements.

Some LR questions present premises (either in the stimulus or in an answer choice) that are not true in real life/in the real world, but for the sake of solving the question logically you have to accept as being factually true and then reason within, meaning that you assume the source (the gremlins that write LSAT questions!) are telling you the truth.
Last edited by Jeffort on Sun Feb 06, 2011 6:37 pm, edited 1 time in total.

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Re: Dumb Question

Postby AreJay711 » Sun Feb 06, 2011 6:37 pm

Jeffort wrote:Although interesting for philosophical discussion, I think this is straying away from the pragmatics of how to deal with assumptions as they relate to properly analyzing LSAT LR arguments


This. In real life what you are saying is true OP but on the LSAT you should always only work with what is there. There are questions that ask you "what assumption makes the conclusion follow logically" and it would be "You should eat delicious things" (or "you should eat apples" or "you should eat anything that is not pork" <--- those bastards can be tricky).

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Re: Dumb Question

Postby AreJay711 » Sun Feb 06, 2011 6:47 pm

JazzOne wrote:
brickman wrote:Alright, let me try something else.

An example:

In making a decision as to whether or not to buy a house, all that the potential owner wants is a comprehensive report on neighborhood demographics. The realtor provides him with a packet of information detailing schools, parks, number of children/household, average annual income, and cultural attractions. The owner makes a decision on the house.

So making a decision requires a comprehensive report and he gets data from a realtor.

The conclusion assumes the validity that the decision was made on the basis of a comprehensive report. What's the premise...well, he got some data from the realtor. Are we saying that the assumption isn't that the data provided isn't sufficient to necessitate the validity of the conclusion?

It feels like the argument is assuming the realtors data is sufficient to say that it is a comprehensive report and thus that a decision can be made.

what am I missing here....

This is a tough example to analyze because the conclusion is implicit. There are several different conclusions we could draw from this argument.

For example, this argument may be intended to prove that the potential owner's desire for a comprehensive report was satisfied. If that's the conclusion, then the assumption is that the owner would not make a decision unless his desire was satisfied.

However, the argument could be intended to prove the stronger conclusion that the report is in fact a comprehensive report. In that case, the argument is making an additional assumption that the owner's desire would be satisfied only by objective truth.

Based on the penultimate sentence of your post, I assume you are construing the argument to defend the stronger conclusion. So, the report, in and of itself, is not sufficient to draw the conclusion, and the argument does not suggest that. Rather, the argument suggests that the combination of the report plus the other two premises is sufficient to draw the conclusion. Like I said in a previous post, the assumption is more nuanced than your articulation, and the assumption pertains to how the unstated ideas fit into the framework of the stated ideas. I suggest that the unstated premises (assumptions) fit into this particular argument as I outlined above.


As for this -- I don't think the OP's example was really an argument but rather a bunch of facts. At best what we can conclude is a conditional statement like:

"If the buyer got all that he wanted before buying the house (and the realtor gave him no other materials), then a comprehensive report contains no more than information detailing schools, parks, number of children/household, average annual income, and cultural attractions".

Thats a nearly worthless conclusion but it is all we can come up with without making an assumption and that is a no-no on the lsat. What it would be more like it would be another part reading part of the conditional statement.

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brickman
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Re: Dumb Question

Postby brickman » Sun Feb 06, 2011 7:39 pm

thank ya, thank ya. I was just thinking about this the other day in terms of actual use of this investigation.

I'm just trying to figure out how to make the optimal use of my time in understanding the content.

Beyond just the standard advice, do you think it would be advisable to pay special attention to just flaws in general just to understand how arguments break down in a limited and predictable manner?

Also,

AreJay, isn't it an argument?

There is a necessary condition that must be fulfilled for something to occur, we have something that would purport to be sufficient to satisfy it, and then we conclude that something occurs.

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JazzOne
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Re: Dumb Question

Postby JazzOne » Sun Feb 06, 2011 7:53 pm

brickman wrote:thank ya, thank ya. I was just thinking about this the other day in terms of actual use of this investigation.

I'm just trying to figure out how to make the optimal use of my time in understanding the content.

Beyond just the standard advice, do you think it would be advisable to pay special attention to just flaws in general just to understand how arguments break down in a limited and predictable manner?

Also,

AreJay, isn't it an argument?

There is a necessary condition that must be fulfilled for something to occur, we have something that would purport to be sufficient to satisfy it, and then we conclude that something occurs.

The problem is that the conclusion wasn't stated in the argument. That is not necessarily a fatal flaw. There are examples of arguments with implicit conclusions, particularly on older LSATs. But your set of premises could be construed to support several different conclusions, and I was only able to determine which conclusion you intended based on your subsequent comments about the argument.

I don't agree with the posters above who claim that philosophical analysis is unimportant. The strategies are sometimes gimmicks that, while they may help you identify correct answers, may impede your understanding of logic when you get to law school and require a more abstract conception of argumentation. I'm not arguing against direct strategies like the negation test. But I also think it's important to ruminate on the underlying logic of the strategy and the arguments to which it is applied.

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Re: Dumb Question

Postby artichoke » Sun Feb 06, 2011 8:09 pm

God I love TLS

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JazzOne
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Re: Dumb Question

Postby JazzOne » Sun Feb 06, 2011 8:22 pm

AreJay711 wrote:
brickman wrote:In making a decision as to whether or not to buy a house, all that the potential owner wants is a comprehensive report on neighborhood demographics. The realtor provides him with a packet of information detailing schools, parks, number of children/household, average annual income, and cultural attractions. The owner makes a decision on the house.

As for this -- I don't think the OP's example was really an argument but rather a bunch of facts. At best what we can conclude is a conditional statement like:

"If the buyer got all that he wanted before buying the house (and the realtor gave him no other materials), then a comprehensive report contains no more than information detailing schools, parks, number of children/household, average annual income, and cultural attractions".

Thats a nearly worthless conclusion but it is all we can come up with without making an assumption and that is a no-no on the lsat. What it would be more like it would be another part reading part of the conditional statement.

I agree with you that the argument is a bunch of facts, but I think those facts are arranged to imply certain conclusions, including one similar to what you have stated.

The most natural interpretation of the first sentence is that the potential owner will not make a decision unless he gets what he wants (or thinks he got it), i.e., a "comprehensive report . . . ." The owner does make a decision, so we can conclude that he got what he wanted. (I think it's more appropriate to say that his desire was satisfied because it could be that he thinks he got what he wanted but he is actually mistaken. Let's ignore that distinction for now.) However, my prior analysis was flawed to the extent that it ignored the description of the packet. So, the most logical conclusion of this argument is "the potential owner considered a packet of information detailing schools, parks, number of children/household, average annual income, and cultural attractions to be a comprehensive report on neighborhood demographics." That articulation incorporates all the information in the most logical way.




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