Q16 - Anyone who believes in

[ohthatpatrick]

What does the Question Stem tell us?
Match the Flaw

Break down the Stimulus:
Evidence:
If you believe in ET's, then you believe in UFO's.
But UFO's do not exist.

Conclusion:
Therefore, It's false to believe in ET's (i.e. "ET's do not exist.")

Any prephrase?
Cleaning this us, we're hearing that "if you believe in X, you believe in Y". Since a belief in Y is false (conclusively refuted), then a belief in X is also false. It sounds like a contrapositive, but you can't use that logic on an association between beliefs. Belief X might be a true belief and Belief Y might be a false belief. For example, it's possible that "Everyone who believes that water's molecular structure is H20 also believes that Santa Claus is real. Since Santa Claus is not real, we know that water's molecular structure is not H20." We need a conditional statement that relates belief 1 to belief 2, a fact that belief 2 is wrong, and a conclusion that belief 1 must also be wrong.

Correct answer:
A

Answer choice analysis:
A) Looks good: If you believe in U, you believe in C. Since a belief in C is wrong, a belief in U is wrong. The weirdness is the fact that we're equating "a belief in centaurs is false" with "there are no centaurs". Is that fair to equate? Seems like it. All we mean by "believing in centaurs" is "believe that they exist". So if that belief is false, then we're saying "they don't exist".

B) Same setup, but instead of getting "a belief in C is wrong", we get "YOU don't believe in C", so "YOU don't believe in U". This is actually valid logic.

C) Same setup, and same problem with the 2nd ingredient. As it turns out, this argument is an illegal negation, but that wasn't the problem with the original argument.

D) This is very tempting. But instead of dealing with whether beliefs 1 and 2 are true vs. false, we're dealing with whether they're justified / unjustified. Those are different enough to make (A) a closer match.

E) This is also tempting. But it has a different structural order from the original. The original tried to argue about beliefs using the contrapositive. (Belief 2 is wrong, thus belief 1 is wrong). This tries to argue about beliefs using an illegal negation (belief 1 is wrong, thus belief 2 is wrong).

Takeaway/Pattern: Many times, Match the Flaw does not get nit-picky about replicating the exact same recipe of ingredients, as long as the Flaw is adequately replicated. On this one, A vs. E comes down to noticing whether the author argues via a contrapositive or a negation. Start by looking for the same Flaw, and if there are two answers that commit the same flaw, THEN start caring about the nitty-gritty ways in which the ingredients do or don't match.

#officialexplanation

[ManhattanPrepLSAT1]

This is a tough Match the Flaw question.

Stimulus
Anyone who believes in X believes in Y. Y has been demonstrated false, therefore X is false is well.

(A) Anyone who believes in unicorns believes in centaurs. It has been demonstrated that there are no centaurs, so there are no unicorns as well. This seems to match fairly well.
(B) says that "you do not believe in centaurs" when it should have said that "the existence of centaurs has been demonstrated to be false."
(C) says that "you do not believe in centaurs" when it should have said that "the existence of centaurs has been demonstrated to be false."
(D) is really close and if you're looking mostly at the conclusion (D) appears to be a better answer than (A). However, the evidence says "there is no good reason to believe in centaurs" when it should have said that "the existence of centaurs has been demonstrated to be false."
(E) does not have the relationship order reversed as happens in the stimulus. So answer choice (E) is more like Anyone who believes in X believes in Y. X has been demonstrated false, therefore Y is false is well. Compare to above and it's different.

[ryan.oconnor110]

I bit on this one and chose D. Reviewing, I did notice that A is more attractive than D but am still a little uncertain why it is better than D. Could you provide some insight?

[gyfirefire]

I chose (D) as well since (A)'s conclusion doesn't seem right to me, which, i thought, should have been "...so a belief in unicorns is false" with emphasis on the "belief in unicorns". That's why i took (D)....but i guess what's in (D) "there is no good reason to believe in centaurs" is not the same as saying "the existence of centaurs has been refuted"

So, if you don't think (A)'s conclusin matches with the simulus, you would choose (D); if you don't think (D)'s premise doesn't match, you would choose (A).

Please help!
Thanks a lot.

[ManhattanPrepLSAT1]

So I just noticed something on this question that I hadn't noticed before. Thanks gyfirefire!

You put things into perspective for me as soon as I read

So, if you don't think (A)'s conclusin matches with the simulus, you would choose (D); if you don't think (D)'s premise doesn't match, you would choose (A).

If you look very carefully, the conclusion of answer choice (D) also doesn't match the stimulus as well as it first sounds. Saying something is "unjustified" is the same as saying that it's "unproven" but that's not the same thing as saying that it's "false."

The conclusion of the stimulus is that "a belief in extraterrestrials is false." That is much stronger than saying that a belief is unjustified.

Maybe that will help nudge us a bit closer to answer choice (A)

That's the amazing thing about the LSAT; I continue to see new things even after I've gone through a question dozens of times!

[lovelessim]

I chose "E" on this one. I weeded out "D" because of the "no good reason" term and that "A" was wrong because it left out "belief". I now see that stating a belief is false is equivalent to stating that there are none of the thing in questions, but I am still confused on "E". I see that they have switch around X and Y, but how does this change the flawed reasoning? Isn't the flaw still intact?

[ManhattanPrepLSAT1]

Not exactly...

The stimulus says "anyone who believes in in extraterrestrials believes in UFOs." BE ---> BUFO

in this case there could still be some people who believe in UFOs but do not believe in extraterrestrials.

That's different than saying, "anyone who believes in UFOs believes in extraterrestrials." BUFO ---> BE

in this case there could still be some people who believe in extraterrestrials but who not believe in UFOs.

I know the difference is subtle but it impacts the flaw. This is commonly referred to as a reversal. Since we're trying to match the flaw, and answer choice (E) commits a reversal (as compared with the stimulus), it cannot be the correct answer

Does that help clear up why the flaw in answer choice (E) is not still intact?

[todavidzheng]

on a side note, could anyone please elaborate why the question is a flawed reasoning?

thanks!

[ManhattanPrepLSAT1]

Sure. Think of the first sentence as establishing a relationship between those who believe in extraterrestrials and those who believe in UFOs. That relationship has nothing to do with whether either of those beliefs are true or false. The way the information is presented, one might think that the argument relies on a contrapositive. But the correct contrapositive would be, "if one does not believe in UFOs, then one does not believe in extraterrestrials." No conclusion could use that relationship to establish a conclusion about whether or not extraterrestrials actually exist.

Does that make sense?

[LSAT-Chang]

Hey Matt, I have one quick question in regards to (A).

The stimulus concludes: "a BELIEF in extraterrestrials is false" whereas the answer choice concludes: "there are NO unicorns". How can these be the same? A belief being false = something not existing??? That seems so weird to me... and since it is Q16, it seems even weirder since we need to be on the lookout for these types of shift in meaning...

[mcrittell]

Matt, can you follow up on changs' latest post bc I too have a similar concern. I thght that the conclusion in A should've read "so there are no BELIEFS in unicorns either." Thanks

[timmydoeslsat]

I think we can all agree that what happens in this stimulus is:

Believe ETs ---> Believe UFOs

~UFOs
________________________
~ETs


Our initial premise was a conditional concerning belief. The fact that there are not UFOs would not give us just reason to conclude that there are not ETs.

To say that a belief is false is to say that the thing does not exist.

If we know for a fact that your belief is false, then that belief does not exist. The conclusion of this argument is a clever way of saying that ETs do not exist.

The conclusion is not a negation of our sufficient condition in the first premise. A belief can be false, yet people can still believe it.

If we keep in mind how this argument is constructed: Conclusive proof of one thing not existing and arriving at a conclusion of another thing not existing, we can arrive at (A) confidently.

(D) does not conclusively refute the existence of something, and the conclusion is not a refute of the existence of something, it simply says it is unjustified.

[ManhattanPrepLSAT1]

Nice work Timmy! That's exactly right. This question is a clever play on the difference between something being unproven and something being false.

The LR section does this a lot on ID Conclusion questions. Check out:

PT41, S3, Q18 - Tallulah: The columnist attributes

In the stimulus, saying "a belief in extraterrestrials is false," is equivalent to suggesting that, "there are no unicorns."

Both of these are different than suggesting that "a belief in extraterrestrials is unsupported," or that "a belief in unicorns is unjustified."

Hope that helps!

[lhermary]

I got this one wrong because of the word 'refute'. The definitions are as follows:

re·fute (r-fyt)
tr.v. re·fut·ed, re·fut·ing, re·futes
1. To prove to be false or erroneous; overthrow by argument or proof: refute testimony.
2. To deny the accuracy or truth of
http://www.thefreedictionary.com/refuted

1. matches up with the way the word was used in the stimulus. However, I thought the definition of refute was #2, which is why I crossed off A and chose D. The LSAT seems to play around with the vagueness of words to the point where I'm left with two or three definitions of what a something means. It's really frustrating. Can one of the Geeks help me out this this?

Thanks

[timmydoeslsat]

To say that something has been conclusively refuted means that something has been demonstrated to not be true.

The second example of refute you bring up is more about a single person defending an idea: John refuted the notion of him being at the house at 3 PM.

That is a separate issue of saying that an idea has been refuted.

[eapetrilli]

As someone who mistakenly chose (E), this argument makes better sense when I consider the different ways the concept of belief has been used. The conditional involves someone subjectively believing in something, while the conclusion refers to the objective truth of a belief about something.

(A) makes the same mistake, but without the word "belief" used in the conclusion. However, saying that what the belief refers to doesn't exist is the same thing as saying that the belief itsel is false.

Therefore (A) has similarly flawed reasoning because both arguments illicitly infer that the conditional has been triggered from a premise that deals with the the objective falsity of a belief but not the subjective lack of belief. The accuracy of belief and the existance of belief are two different concepts.

[randitect]

I don't understand why the order matters.

I chose E over A because of the wording (beliefs), but that issue aside, I am having difficulty understanding why it is important to match the order (centaurs then unicorns or unicorns then centaurs) in the two arguments.

Thanks in advance.

[rickytucker]

This is a parallel-flaw question which means it's a two-parter: we are asked to match both (1) the flaw and (2) how the flaw is incorporated in the reasoning of the argument.

First, the flaw is an uncertain use of a term or concept in that it equivocates with respect to the term "belief". That is to say, it fallaciously equates "believing in something" to mean the exact same thing as an affirmation of "the existence of that thing".

Second, the reasoning structure in the argument is sound: X --> Y thus, ~Y --> ~X.

Combining these two points the correct answer is (A) because it is the only answer that parallels both the equivocation flaw and the correct incorporation of that flaw into the reasoning of the argument.

This is the flaw:
Belief in extraterrestrials (BE) = Existence of extraterrestrials (EE)
Belief in UFOs (BU) = Existence of UFOs (EU)

This is how the stimulus incorporates that flaw:
If BE (EE) --> BU (EU). Since ~BU (~EU) --> ~BE (~EE).

Answer choice (A) says:
If BU (EU) --> BC (EC). Since ~BC (~EC) --> ~BU(~EU).

(B) is wrong because it doesn't include the equivocation flaw, that is to say, it's sound logic.

(C) is wrong because it includes neither the equivocation flaw nor the same reasoning structure (mistaken negation).

(D) is close since it does have both the flaw of equivocation ("belief" = "belief is justified") as well as the same reasoning structure but (A) is closer because its equivocation flaw uses parallel terms compared to the stimulus ("belief" = "existence").

(E) is wrong because it doesn't have the same reasoning structure (mistaken negation).

[ricardo.e.miranda]

I got this one wrong during a timed practice. I originally chose (E). But went back and read it again without being timed. The second time through, I noticed that the logic structure was analogous to:

Sentence 1: if E --> U (if E then U).
Sentence2&3:
But, Not U --> Not E (But, Not U therefore Not E)

(a) Yes. if U --> C (if anyone believes in unicorns then they also believe in centaurs. But, Not C --> Not U (there are no centaurs, so there are no unicorns). This follows the same structure as the passage.

(b) No. This one had the same structure as the passage except that it focused on "you" and is why I scratched this as a possible answer.

(c) No. Not the same structure. This structure is more of the type U-->C but NOT U therefore NOT C. For this argument to be of same structure would have to say NOT C therefore NOT U.

(d) Maybe. Same structure but here is comparing the use of the phrase "has been conclusively refuted" in the stimulus with "there is no good reason to believe" in the answer choice. This is what made D tricky. So not sure yet what logic to use in rejecting D and picking A as a better answer.

(e) No. Wrong structure, same logic as (c).