Question two: All Labrador retrievers bark a great deal. All St. Bernard's bark
infrequently. Each of Rose's dogs is a cross between a Labrador Retriever and a
St. Bernard. Therefore, Rose's dogs are moderate barkers.
Alright so argument or facts and clearly we have an argument. Therefore structural indicator. Our
conclusion here is that Rose's dogs are moderate barkers. And how do we know that?
Well, our first premise is that all Labrador Retrievers bark a great deal and then
all St. Bernards bark infrequently. Rose's dogs are cross between these two types of
dogs therefore they must have moderate barking.
Just to break down this passage we know that 'all' is sufficient and necessary
terminology that introduces a sufficient condition. So our our sufficient condition would be 'Labrador
Retriever' and our necessary condition would be the other part of statement 'bark
a great deal'. You notice the next sentence we also have 'all'. So again 'all' introduces sufficient so St.
Bernard would be my sufficient condition. My necessary condition would be bark
infrequently. So basically we have this spectrum of barking and we have Labrador
Retrievers on one side and St. Bernard's on the other.
This is infrequently whereas Labrador Retrievers
bark a great deal. It tells us that Rose's dogs are a cross between these two
types of dogs, Labrador Retrievers and St. Bernards, to conclude that Rose's dogs
are moderate barkers. Clearly a flawed argument. How can we say that just
because Labrador Retrievers bark a great deal St Bernards Berndards bark infrequently
Rose's dogs are a cross. Therefore they must be moderate barkers. Doesn't make any sense
but now that we have a clear understanding of this argument and we've
identified that it is a flawed argument we turn our attention to the question stem.
Which one of the following uses flawed reasoning that most closely resembles
the flawed reasoning used in the argument above. So, you notice they point out for us that this is
a flawed argument just in case you didn't notice. Again this is a flawed
parallel resoning question. So now were going to look for an answer choice that has this exact same
flaw, basically taking two sufficient and necessary conditions where you have Labrador
Retriever sufficient for barking a great deal, St. Bernards sufficient for barking
infrequently. Then have a combination of these two sufficient conditions to conclude that
for some reason we're in the middle of the necessary conditions. Let's take a
look at (A). All students who study diligently make good grades but some
students who do not study diligently also make good grades. Jane studies
somewhat diligently therefore Jane makes somewhat good grades. You noticed that (A) while
flawed is not the same flaw that we saw in the passage so (A) would be eliminated.
You notice 'all' again introduces sufficient so if you study diligently you make good grades
and then tells us that Jane studies somewhat diligently so therefore she
makes somewhat good grades. So that clearly makes no sense just because you have somewhat
of the sufficient condition it doesn't mean you have somewhat of the necessary
condition but that is not the problem that we saw in our passage so (A) would
be eliminated. Moving to (B): All types A chemicals are extremely toxic to human
beings all type B chemicals are non-toxic to human beings this household
cleaner is a mixture of a type A chemical and a type B chemical therefore
this household cleaner is moderately toxic.
You notice just based on structure (B) seems like it's dead on but let's make
sure. Again we know 'all' introduces sufficient so if you are type (A) you are extremely toxic.
If you are type (B) you are not toxic. So again we have this spectrum. We have type (A) we have
to (B). Again extremely toxic while (B) is non-toxic. It theb tells us that this household cleaner is a mixture
of type A and type B to conclude that it is moderately toxic. And you
notice that is the exact same flaw in the passage. We took two sufficient
and necessary statements and then because something was a mix of the
sufficient conditions we concluded that we have the middle of the necessary conditions.
Right? Moderate Barkers. And in (B) we took the fact that A is extremely toxic B is
non-toxic this household cleaner is a mixture of A and B
therefore it is moderately toxic. Exact same flaw so (B) would be the correct
answer. But again just making sure (C): All students and Hanson school live in
Green County. All students at Edwards school live in Winn County. Members of the
Perry family attend both Hansen and Edwards. Therefore, some members of the
Perry family live in Greene County and some live in Winn County. Again (C)
is a valid argument so it clearly cannot work. We are looking for
flawed argument so (C) is out. Again you notice that 'all' again intoduces
So if you go to Hanson school that is sufficient for living in Greene County. If you go to
then you live in Winn County. Some members right of the Perry family attend
both Hanson and Edwards. So we have people at Hanson school. We have people
at Edwards School. And it takes that to conclude therefore we have some members
of the Perry family living in Greene County and some living in Winn County. It's a valid argument.
So (C) again would be eliminated just based on that we're looking for a flawed
argument. Moving to (D): All transcriptionists know shorthand. All
engineers know calculus. Bob has worked as both a transcriptionist and as an engineer.
Therefore Bob knows both shorthand and calculus. Again (D) is a valid argument. So how
could (D) be the correct answer? Again if you are a transcriptionist you know
shorthand. If you are an engineer you know calculus. Bob has worked both as a
transcriptionist and an engineer and take that to conclude that he knows
shorthand and he knows calculus. Again, valid argument
invoking sufficient to conclude necessary. But again not what we're looking for here.
We're looking for a flawed argument which brings us to (E): All of Kenisha's dresses
are very well made. All of Connie's dresses are very badly made. Half of the
dresses in this closet are very well made, and half of them are very badly made.
Therefore, half of the dresses in this closet are Kenisha's and half of them
are Connie's. Clearly a flawed argument. But is it the same flaw? You notice that it is
not. The problem here is that were saying if you were made by Keisha, Keisha's dresses are very
well made. It then tells us that all of Connie's dresses are very poorly made or very badly made.
Half of the dresses in this closet are very well made and half of them are
very badly made. It then takes that to conclude that half of them are Kenisha's
and half of them are Connie's but again the existence of the necessary condition
tells us nothing about whether sufficient is present or not. Again just because
I am a vegetable it doesn't necessarily mean I'm a carrot. We know all carrots are vegetables but you
cannot say because something is a vegetable it is also a carrot. That is
what's happening in (E). Don't just reverse but
you notice again not the flaw we saw in the passage so (E) is eliminated.