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 jlam061695
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#31017
I know why D is correct, but what makes E incorrect? Is "publicly oppose extending" synonymous with "refusing to support publicly"? Or is this a shell game answer?
 Adam Tyson
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#31065
Hey there jlam! The problem with E is that "publicly oppose" is NOT synonymous with "refuse to publicly support". We have no way of knowing if anyone is publicly opposing anything. That's why D is better than E - D must be true, and E has no evidence to support it.

Remember to look for which answer is "better", not which answer is "right" or "wrong". It's not about what makes E wrong, but what makes D better.

Good luck!
 Kaylahernandez
  • Posts: 3
  • Joined: Aug 29, 2017
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#40550
I got the correct answer on this question but was very hesitant with my answer because of the "not all." The stimulus said "Some" which I understand to mean "everything but all" so because this is a must be true, I figured I could not prove "not all" as stated in the answer. Am I missing something or just over analyzing?
 James Finch
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#40643
Hi Kayla,

"Some" can, but does not necessarily, mean "all;" "some" is synonymous with "more than none" for LSAT purposes, and its logical opposite is "none." Similarly, "all" and "not all" are the other logical opposites that we have to keep in mind, with "not all" meaning any number fewer than all of a group, up to and including none.

For this question, we have premise that gives us one group which then splinters into two groups, and we have to use the language given to keep track of the possible overlap between the two groups. Because we are given that "some" of the pro Canada/US/Mexico free trade politicians do not publicly support extending free trade to other Latin American countries, we can deduce that not all pro Canada/US/Mexico free trade politicians now publicly support extending free trade to other Latin American countries. The answer to the question becomes clear when we use this deduction to prephrase our answer and test it against the given answer choices.

"The issue here with "not all" is keeping track of which group it is referring to. Answer choice (B) gives us the reverse of our inference, that not all politicians now publicly supporting the extension of free trade to other Latin American countries supported Canada/US/Mexico free trade, but we don't actually know anything about that group other than that it doesn't include all those politicians that strongly supported Canada/US/Mexico free trade in the past. (D) however gives us answer very close to our prephrase, which is the only inference we can logically make based on the premise given in the stimulus.

Hope that clears things up!
 mcioci
  • Posts: 3
  • Joined: Oct 15, 2017
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#41887
Hello,

Is this argument conditional at all and can it be diagrammed? I tried to do the following: "If some politicians strongly support free trade among Canada, the United States, and Mexico then they refuse to support publicly the of extending free trade to other countries." The "not all" in D made me think it was a mistaken negation. Answer B kind of seemed to match the contrapositive but I am not sure if this question is even conditional and if I should have diagrammed it.

Thanks,
Michael
 Francis O'Rourke
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#41928
Hi Mcioci,

I personally would not diagram the argument, because I feel that it is easier to understand it in other ways. For example, you can diagram the argument in the following way:

Previously supported free trade in N.A. ..... :longline: some :arrow: ..... Not support free trade with these L.A. countries

I personally summed it up in this way: There is at least one politician who was for that agreement, but who is not supporting this one.

Of course, I did not write this down. If I can comprehend a single, simple statement such as this without diagramming it, I don't see the point in diagramming it. For me, translating this statement into a conditional made it more difficult to understand.

Diagramming statements is a tool that should make the test easier for you. If diagramming this statement helped you understand the stimulus, then go ahead and do so! :-D More important than diagramming a statement is accurately reading it. For example it looks like in your diagram that you left out the time shift in the stimulus.
 2020//Vision
  • Posts: 6
  • Joined: Sep 25, 2020
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#79343
Hi there! Would it be possible to request a full breakdown of this question and the answer choices? Am going through the course and just did PT 76. Would this be considered a formal logic question, like in Lesson 8? Are we supposed to use the "some train" technique? Would appreciate a full breakdown of the question and answer choices. Thank you in advance!!
 Jeremy Press
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#79962
Hi 2020,

This question is testing a very simple Formal Logic equivalency, using concepts (specifically long, wordy phrases) that make it much harder to see the equivalency being tested.

Here's the equivalency they're testing: the phrase "Some A's are not B's" is the Formal Logic equivalent of the phrase "Not all A's are B's."

Think about this equivalency using a simple example. "Some law students are not history majors." That means there is at least one (maybe more) law student who is not a history major. If that's true, then it must also be true that "Not all law students are history majors." That's the case because that one (or more) law student who isn't a history major is stopping us from getting to the point where all law students are history majors.

In this question, the equivalency is harder to stop because of the wordiness of the concepts used. But, using brackets, we can see the stimulus as a "Some [A]'s are not 's" type of statement.

Some [politicians who strongly supported free trade among Canada, the United States, and Mexico] are not [supporting publicly the idea that free trade should be extended to other Latin American countries].

Now convert that to our equivalent: "Not all [A]'s are 's."

Not all [politicians who strongly supported free trade among Canada, the United States, and Mexico] are [supporting publicly the idea that free trade should be extended to other Latin American countries]. That's answer choice D!

The other answers are wrong for differing reasons.

Answer choice A: Answer choice A is the equivalent of saying "Some B's are not A's." That attempts to create a "contrapositive" style relationship from the "Some A's are not B's" statement in the stimulus. In Formal Logic, "some" statements do not have valid contrapositives. Use this simple example as proof of that: "Some dogs are not Golden Retrievers." That doesn't permit the inference that "Some Golden Retrievers are not dogs."

Answer choice B: Answer choice B is the reversal of the equivalent phrase we're looking for. Recall that the phrase we're looking for is "Not all A's are B's." Answer choice B reverses that to say that "Not all B's are A's." In Formal Logic, "not all" statements do not necessarily imply their reversals. Use this simple example as proof of that: "Not all dogs are Golden Retrievers." That doesn't necessarily imply that "Not all Golden Retrievers are dogs."

Answer choice C: We do not know what the politicians' general "positions" on free trade were at the time they "strongly supported free trade among Canada, the United States, and Mexico." Without knowing that, we cannot know whether those general positions have changed. It's possible that there are legitimate differences in free trade among Canada, the U.S., and Mexico versus free trade with other Latin American countries. There's no way to tell this kind of general consistency without more information in the stimulus.

Answer choice E: Quoting Adam's excellent post on this answer above, Adam correctly says, "The problem with E is that 'publicly oppose' is NOT synonymous with 'refuse to publicly support'. We have no way of knowing if anyone is publicly opposing anything." To supplement this a bit, I might "refuse to publicly support" legislation raising taxes, meaning I don't offer any statements supporting such legislation. That does not mean I've come out and directly opposed (i.e., stated that I'm against legislation raising taxes.

I hope this helps!

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