New elements in the conclusion of Assumption questions

epark84
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New elements in the conclusion of Assumption questions

Postby epark84 » Sun Mar 27, 2011 7:06 pm

This is a pretty specific assumption question. I remember learning that when a new element is introduced in the conclusion of an assumption question, then the correct answer choice should include that new element. For example:

All children love eating chocolate cake. Therefore, bobby loves eating chocolate cake.

The new element is Bobby, so the answer choice must include him (Bobby is a child).

Is this new element rule 100% true, for both necessary and sufficient assumption questions?

Thanks.

Logic STUD
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Re: New elements in the conclusion of Assumption questions

Postby Logic STUD » Sun Mar 27, 2011 8:07 pm

You should always be careful at looking for something to be 100%. However in this case, let's not even talk about that because you seem to be off the track entirely. In an assumption question you're looking for something that's assumed.



as·sump·tion (-smpshn)
n.
1. The act of taking to or upon oneself: assumption of an obligation.
2. The act of taking possession or asserting a claim: assumption of command.
3. The act of taking for granted: assumption of a false theory.
4. Something taken for granted or accepted as true without proof; a supposition: a valid assumption.
5. Presumption; arrogance.
6. Logic A minor premise.



Let's really focus in on number 4. Something that is accepted as true without proof. So in an example like you provided, and it's difficult because obviously that's not a real question. We already know Bobby loves eating chocolate cake. We already know that all children love to eat chocolate cake. So if we had answer choices, we'd have to look for something new and unstated. Therefore, the correct answer is very unlikely to include the new element. (Bobby)


-LS

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EarlCat
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Re: New elements in the conclusion of Assumption questions

Postby EarlCat » Mon Mar 28, 2011 3:11 am

epark84 wrote:Is this new element rule 100% true, for both necessary and sufficient assumption questions?

No, but close.

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EarlCat
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Re: New elements in the conclusion of Assumption questions

Postby EarlCat » Mon Mar 28, 2011 3:15 am

Logic STUD wrote:We already know Bobby loves eating chocolate cake. We already know that all children love to eat chocolate cake. So if we had answer choices, we'd have to look for something new and unstated. Therefore, the correct answer is very unlikely to include the new element. (Bobby)

No. In most of these arguments there is an element in the premise that is not in the conclusion, and an element in the conclusion that is not in the premise. The assumption usually just ties these two things together. So OP is right. We don't know that Bobby loves eating chocolate cake based on the given premise [/i]unless[/i] we assume that Bobby is a child. "Bobby" will almost certainly appear in the answer.

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Easy-E
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Re: New elements in the conclusion of Assumption questions

Postby Easy-E » Tue Mar 29, 2011 3:37 pm

EarlCat wrote:
Logic STUD wrote:We already know Bobby loves eating chocolate cake. We already know that all children love to eat chocolate cake. So if we had answer choices, we'd have to look for something new and unstated. Therefore, the correct answer is very unlikely to include the new element. (Bobby)

No. In most of these arguments there is an element in the premise that is not in the conclusion, and an element in the conclusion that is not in the premise. The assumption usually just ties these two things together. So OP is right. We don't know that Bobby loves eating chocolate cake based on the given premise [/i]unless[/i] we assume that Bobby is a child. "Bobby" will almost certainly appear in the answer.



By saying "all children" and not "only children", doesn't it mean Bobby could technically love chocolate cake and not be a child? Or will this kind of ambiguity be a non-issue since only one choice can be correct? Or am I just wrong?

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incompetentia
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Re: New elements in the conclusion of Assumption questions

Postby incompetentia » Tue Mar 29, 2011 3:43 pm

emarxnj wrote:By saying "all children" and not "only children", doesn't it mean Bobby could technically love chocolate cake and not be a child? Or will this kind of ambiguity be a non-issue since only one choice can be correct? Or am I just wrong?
This would be irrelevant, since making that assumption is sufficient for the conclusion to be drawn.



In the case of more involved assumption questions, a simple diagram can often help clarify. It'll usually be something like:

A->B given
A->C concluded
B->C is your correct answer

or

A->B given
C->D given
A->D concluded
B->C is your correct answer

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Easy-E
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Re: New elements in the conclusion of Assumption questions

Postby Easy-E » Tue Mar 29, 2011 3:48 pm

incompetentia wrote:
emarxnj wrote:By saying "all children" and not "only children", doesn't it mean Bobby could technically love chocolate cake and not be a child? Or will this kind of ambiguity be a non-issue since only one choice can be correct? Or am I just wrong?
This would be irrelevant, since making that assumption is sufficient for the conclusion to be drawn.



In the case of more involved assumption questions, a simple diagram can often help clarify. It'll usually be something like:

A->B given
A->C concluded
B->C is your correct answer

or

A->B given
C->D given
A->D concluded
B->C is your correct answer



Ohh I follow. The correct response is just going to be the the missing step (assumption), regardless if its the only possible or simply one possible one. Thank you for clarifying.

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EarlCat
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Re: New elements in the conclusion of Assumption questions

Postby EarlCat » Tue Mar 29, 2011 6:53 pm

emarxnj wrote:By saying "all children" and not "only children", doesn't it mean Bobby could technically love chocolate cake and not be a child? Or will this kind of ambiguity be a non-issue since only one choice can be correct? Or am I just wrong?

If it were "only children," you couldn't conclude that Bobby loves chocolate cake by merely knowing he is a child. You could only conclude that he didn't love it if he weren't a child.

By saying "all children," it is possible that Bobby would like chocolate cake even if he weren't a child. However, this is irrelevant because we're looking for an assumption necessary to this argument, which concludes Bobby likes chocolate specifically because children do.

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EarlCat
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Re: New elements in the conclusion of Assumption questions

Postby EarlCat » Tue Mar 29, 2011 6:54 pm

incompetentia wrote:A->B given
C->D given
A->D concluded
B->C is your correct answer


B --> D and A --> C are also sufficient.

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Easy-E
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Re: New elements in the conclusion of Assumption questions

Postby Easy-E » Tue Mar 29, 2011 8:52 pm

EarlCat wrote:
emarxnj wrote:By saying "all children" and not "only children", doesn't it mean Bobby could technically love chocolate cake and not be a child? Or will this kind of ambiguity be a non-issue since only one choice can be correct? Or am I just wrong?

However, this is irrelevant because we're looking for an assumption necessary to this argument, which concludes Bobby likes chocolate specifically because children do.


Yeah, I guess I was just getting caught up in the wording, when its the context that matters in this case.

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incompetentia
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Re: New elements in the conclusion of Assumption questions

Postby incompetentia » Tue Mar 29, 2011 11:36 pm

EarlCat wrote:
incompetentia wrote:A->B given
C->D given
A->D concluded
B->C is your correct answer


B --> D and A --> C are also sufficient.

This is true, and also a common thing they do to try to trip people up.




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