PT 59 SECTION 3 LR #19 BABIES Forum

[JJDancer]

OK I understand that the stimulus is not to be taken for granted..because it is one big conditional based on whether the first statement is true or not

If (UW --> KDD) --> (UW--> UW in def)
There are people (ALL babies) who do not KDD of some words they utter
-KDD --> -UW
but this doesn't tell us anything.

I chose A because "some babies" is a subset of all babies and I thought i needed to connect understanding words and "uttering" them somehow...

I get that E makes sense because it says if some babies UW without KDD then the big conditional up top falls apart.

But why is A wrong exactly? because it is assuming that UW --> KDD?
because if we don't assume that, then babies could potentially understand words that they utter (even if they don't know the dic defs as stated in stimulus) ?

[JJDancer]

bump

[incompetentia]

Correct.

UW > KDD is not stated as GIVEN information, but rather the PREMISE of another logical conclusion. I had A marked on this, but after staring at it for 3 minutes, I did eventually choose E.

If we approach this using sort of an LG-ish method, you have:

Case 1: UW > KDD. Therefore UW > KW/DD
Case 2: UW not nec. > KDD. No conclusion can be drawn.

Given the fact that B !> KDD.

Case 1: B !> KDD ---> B !> UW. A would be correct under these circumstances.
Case 2: B > UW is NOT ruled out. A therefore does not logically follow.

If we look at E, however:

Case 1: Invalidated by the wording of the answer choice.
Case 2: B > UW. UW not nec. > KDD. B !> KDD is therefore still possible - we have a winner.

[JJDancer]

Thanks incompetentia

I still don't think I really get the hang of this one though.

Also, what is B"!" ?

[incompetentia]

Oh, it's programming shorthand...means "not" or something similar to that.

So since we're given the example in the premise that babies do not know the dictionary definitions of the words they use...B !> KDD

[JJDancer]

Ugh. Still having a hard time with this.
Is A wrong just because the stimulus is a huge conditional and answer choice A doesn't state that
"understanding a word DOES always involve knowing dict def. therefore, some babies utter individual words they do not understand" ?

[Hedwig]

What was this? A must be true/inference question?

I initially chose A, like you. However, because the premises were not necessarily true, I didn't feel like they 100% supported A. Like, the stimulus is based on an IF so you can't say definitively that some babies don't understand words they utter. It COULD be wrong because the IF premise could be wrong. Whereas E most definitely is true no matter what.

[JJDancer]

What was this? A must be true/inference question?

I initially chose A, like you. However, because the premises were not necessarily true, I didn't feel like they 100% supported A. Like, the stimulus is based on an IF so you can't say definitively that some babies don't understand words they utter. It COULD be wrong because the IF premise could be wrong. Whereas E most definitely is true no matter what.

Yeah it was a which can be logically inferred. Thanks. I get it now.

In general, if I see the premise in LR as a conditional
ex: (If A--B) --> (-A --> C)
Should I look for things that are true regarless of whether "if A --> B" and be wary of answer choices that assume the first conditional as fact?