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 MichaelJAG
  • Posts: 12
  • Joined: Aug 21, 2015
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#19650
Thank-you for all of the information thus far; it is really helping, especially the SN indicator words.

I have a question about #5 of the lesson 2 homework. These were my diagrams of the conditional statements:

1) OKG :arrow: LCH (Not LCH :arrow: Not OKG).

2) P :arrow: L (Not L :arrow: Not P).

3) O :arrow: Not CH (CH :arrow: Not O).

Now, I can logically understand why answer choice A is correct: The necessary condition (LCH) is not met, so the sufficient condition (OKG) cannot happen. However, how do I diagram this? Can I not link the conditional statements and their contrapositives to produce this outcome?

In fact, when I tried to link conditional statements and their contrapositives, I produced the complete opposite:

Conditional- O :arrow: Not CH :arrow: Not OKG

Contrapositive- OKG :arrow: CH :arrow: Not O

Answer Choice A: Not OKG :arrow: O.

I am totally lost how they produced this from linking the conditional/contrapositive statements.
 David Boyle
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#19662
MichaelJAG wrote:Thank-you for all of the information thus far; it is really helping, especially the SN indicator words.

I have a question about #5 of the lesson 2 homework. These were my diagrams of the conditional statements:

1) OKG :arrow: LCH (Not LCH :arrow: Not OKG).

2) P :arrow: L (Not L :arrow: Not P).

3) O :arrow: Not CH (CH :arrow: Not O).

Now, I can logically understand why answer choice A is correct: The necessary condition (LCH) is not met, so the sufficient condition (OKG) cannot happen. However, how do I diagram this? Can I not link the conditional statements and their contrapositives to produce this outcome?

In fact, when I tried to link conditional statements and their contrapositives, I produced the complete opposite:

Conditional- O :arrow: Not CH :arrow: Not OKG

Contrapositive- OKG :arrow: CH :arrow: Not O

Answer Choice A: Not OKG :arrow: O.

I am totally lost how they produced this from linking the conditional/contrapositive statements.
Hello MichaelJAG,

The wording and meaning of the stimulus is tricky. One point is that it doesn't mean something isn't offensive, just because the government can restrict it: it could be offensive AND cause harm too. Answer A says "only offensive", leaving it open that other things could be both offensive and harm-causing. (For all we know, ALL harm-causing things are also offensive.)
That noted, one way to diagram answer A is, leaving out the O-for-offensive part (since offensiveness does not either mandate, or preclude, harm),

"slash CH :arrow: slash GRL subscript P"

, that is, "no harm, therefore no letting government restrict that subset of liberty which is publishing". If you really want to insert the O, you can maybe put it in parentheses before the slash CH, to show that the non-harm-causing material is in fact offensive, though only offensive, not harmful. Or you could insert if after the arrow somewhere, to show that that particular literature is offensive.
(Also note that the "except perhaps" in the stimulus mucks things up some, especially re answer B.)

Hope this helps,
David
 MichaelJAG
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#19757
Thank-you again,

Are there additional practice problems for purely conditional reasoning? I have exhausted the problems in the homework book, and even though I think I understand it now, I need more practice specifically on conditional reasoning to solidify the practice. Thank-you.

Regards,

Michael
 David Boyle
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#19761
MichaelJAG wrote:Thank-you again,

Are there additional practice problems for purely conditional reasoning? I have exhausted the problems in the homework book, and even though I think I understand it now, I need more practice specifically on conditional reasoning to solidify the practice. Thank-you.

Regards,

Michael
Hello MichaelJAG,

In the student online resource center, even if there is not a specific "conditional reasoning only" section, there are plenty of logical reasoning problems, many of which are conditional reasoning problems. You can either do all the problems, or just skip through and do only the conditional ones.

Hope this helps,
David
 kristenthompson92
  • Posts: 2
  • Joined: Feb 15, 2016
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#22080
Hello-
I am also having issues with this problem as I am finding that there are no necessary or sufficient indicator words in the answer choices and therefore I am finding it tricky to apply my conditional diagrams.


Are there any tricks for problems, such as this one, where these NC and SC indicators are absent in some if not all of the choices?

Thanks!

Kristen
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 Dave Killoran
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#22090
Hey Kristen,

Please check my answer to your other post and let me know if that helps at all. If not, we'll talk about it further.

Thanks!
 mpoulson
  • Posts: 148
  • Joined: Mar 25, 2016
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#22600
Hello,

I am confused about how to diagram this question. I thought according to the "unless equation" you negate sufficient condition and everything after the "unless" becomes the necessary. However, the explanations for the LR homework don't seem to indicate a negated sufficient (ok to restrict liberty → cases where harm would be allowed). Thank you.

V/r,

Lt Poulson
 Clay Cooper
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#22624
Hello Lt Poulson,

Thanks again for your question.

You are correct to apply the unless equation to this conditional reasoning statement. Let's walk through it.

First, we take the term modified by the unless (or, in this case, the except) and make it the necessary condition. So, what we have is: except when not restricting liberty would cause harm, or

--> would cause harm.

Now, we take the other term, negate it, and make it the sufficient condition. In this case, that term is 'it is wrong for the government to restrict the liberty of individuals', so what we end up with is the following:

~wrong to restrict liberty --> would cause harm.

However, we can simplify the left side (since it currently says it is not wrong...) and express it in terms of, instead, when such restriction is right:

acceptable to restrict liberty --> would cause harm.

This is the correctly diagrammed version of this rule; we can check it by expressing it as a statement of the rule and seeing if that statement reflects what we were originally told. In this case, that statement would be: If it is acceptable to restrict individual liberty, then it must be the case that failing to do so would cause harm.

That appears to me to be an accurate version of what we were told, so we have correctly understood and diagrammed the rule.

Now, if offending is not causing harm, and publishing is a liberty, it follows that answer choice A must be correct, since it can never be justifiable to restrict the liberty to publish just to prevent an offense (which is not actually a harm).

Hope that helps!
 mpoulson
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  • Joined: Mar 25, 2016
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#22722
Clay,

I understand and thank you. I wanted to determine also what made B an invalid choice? My guess was that the information only said "perhaps" which indicates not every case of causing harm is an acceptable reason to restrict liberty. Additionally, a more general question is there a case where instead of using the word "not", the test makers employ another word which has the same effect of negating the condition. For example for the unless equation, other indicators of the equation are until, except, without. Are there similar equivalents for "not" which indicated the condition is negated in the text. Thank you.

-Micah
 Adam Tyson
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#22747
The problem with B here is not the "perhaps", but rather the arrangement of the conditions. Simplifying the claims a bit, using some shorthand and the "Unless Equation" that you and Clay already covered, the first claim is "Wrong --> Harm". Now, look again at Answer B, and focus on the sufficient condition indicator "when". The diagram for this answer choice would be "Harm --> Wrong", and that's a mistaken reversal. A very attractive answer, because it has the right bits and pieces in it, but incorrect because Mistaken Reversals and their twin siblings Mistaken Negations cannot be proven based on the original conditional claims. They might be true - they might even seem like they are probably true - but you just can't prove them.

As to alternatives to "not", I'm pondering that one. All I am coming up with are variations of not, like can't and don't. When I see "impossible" I often think of that as a version of not, so "improvements are impossible" would be Imp --> possible. Come to think of it, all kinds of prefixes that imply negation, like Un- and Anti-, might be deserving of the "not" treatment. Give that some thought and tell us what you think, and especially if you come up with more.
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