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#22938
Complete Question Explanation

Assumption. The correct answer choice is (E)

The argument exposes a common misconception that arises when laypeople interpret scientific theory. In ordinary American English, we think of "fit" as meaning muscular, athletic, and thin. (In British English, "fit" can also have the connotation of "good-looking.") However, in evolutionary biology, "fit" simply means "well-suited to the environment and thus likely to survive." The argument points out that when we hear the phrase "survival of the fittest," we should not construe "fit" in the ordinary English sense. The argument does a good job of proving that the phrase "survival of the fittest" is a tautology: the phrase merely states an obvious point — that the most likely to survive are the most likely to survive.

However, the argument runs into trouble in its very last clause when it suggests that a tautology must necessarily be "neither informative nor of scientific interest." In other words, a tautology has the following properties: (1) It is not informative; and (2) It is not of scientific interest. Where did this logical leap come from? This is a big hole in the argument. In order to make the argument completely air-tight, we must make assumptions which fill in these holes.

Answer choice (A): In order to make the argument work, we need to show some logical connection between a tautology and (lack of) informativeness; and a logical connection between a tautology and (lack of) scientific interest. This answer choice is attempting to relate scientific interest with informativeness — this is not the logical step we need.

Answer choice (B): This answer choice essentially says "If scientific interest, then true." The contrapositive is "If false, then no scientific interest." In order to fill in gaps in the argument, we are attempting to establish "If a tautology, then no scientific interest." So this answer choice does not help us.

Answer choice (C): Try assuming the logical negation of this answer choice: What if popular slogans are often informative or of scientific interest? This would not disprove the author's argument the popular slogan "survival of the fittest" is not informative or of scientific interest. That popular slogans often have certain properties does not imply that popular slogans always have such properties in all cases. So by the Assumption Negation test, the statement in this answer choice is not necessary for the argument.

Answer choice (D): Try assuming the logical negation of this answer choice: What if informative scientific claims can use terms in the way they are popularly used? This would not disprove the author's argument that this particular scientific claim is not using the term "fittest" in its popular sense. So by the Assumption Negation test, the statement in this answer choice is not necessary for the argument.

Answer choice (E):This is the correct answer choice. Every tautology is logically "true," but it may not give us interesting new information. If we say that truth is not sufficient for a claim to be of scientific interest, we remove the possibility that every tautology is of scientific interest. This possibility would destroy the argument.
 LustingFor!L
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#34956
Can someone diagram answer choice E and then show it negated using the assumption negation technique. I am lost on how to diagram not sufficient; does that mean it's necessary or should it be negated as the sufficient?
 Adam Tyson
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#36034
Happy to try that for you, Lusting! First, we have to take note that answer E does NOT set up a conditional relationship, in that it does not tell us that anything is sufficient for anything else. On the contrary, it denies the existence of a conditional relationship by telling us that truth is NOT sufficient for scientific interest.

Now, we could try to force that into a conditional framework, and with some convoluted twists we might get something useful, but it's probably not worth the effort to do so. Just be careful here - we would definitely NOT do this:

Truth :arrow: Scientific Interest

Why not? Because truth does not prove that something isn't of scientific interest in this answer, it's just that it doesn't prove that is IS of such interest. I also would strongly caution you against this one:

Truth :arrow: Scientific Interest

That's also wrong, because the lack of truth doesn't prove anything either.

Frankly, forget about trying to diagram answer E. It's not a conditional claim, and conditionals are just about the only claims that are ever worth diagramming on the LSAT.

However, when we negate this answer, suddenly we do get a conditional claim. Instead of saying that truth is NOT sufficient, let's say that it IS sufficient!:

Truth :arrow: Scientific Interest

This is a conditional claim, and this claim wrecks the argument. The author wants us to believe that a tautology, while true, is of no scientific interest, but if anything true IS of such interest then he must be wrong! The effect of this negation proves that answer E was indeed an assumption required by the argument, and we have ourselves a winner.

Let us know if that helped!
 egarcia193
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#38318
Hi,
I was stuck between C and D in this question and chose C, I don't understand what E is saying or how it is the correct answer. the explanation above just left me more confused, can someone explain What E means and how it is the correct answer?
 Adam Tyson
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#38331
The bad news, egarcia, is that for the moment you are stuck with me, the guy whose explanation didn't cut it for you. Sorry about that! The good news is that I LOVE having the opportunity to explain things another way, because there's almost always more than one approach that could work.

First, let's be sure we understand the argument: "survival of the fittest" is the same as saying "the most likely to survive are the most likely to survive", which is a tautology, and that means it's of no interest.

Now the question stem: what must the author have assumed? What's missing? Try looking for a gap in the argument, something new in the conclusion. "Not interesting" is a paraphrase for that new idea. Link that new thing back to the premises, which talk about truth and tautologies, and you know that you need an answer that connects "not interesting" to "truth". Only answers B and E make that connection, so using this "logical gap" approach should indicate that these are your only contenders.

At this point, since it is an assumption question, you have a clear and virtually infallible test that you could apply to the contenders, and that is our world-famous, award-winning, and truly delicious Assumption Negation Technique (TM). Negate (make false) each of those contenders, and the one which, when negated, wrecks the argument is the right answer.

Answer B can be negated as "some untrue claims are of scientific interest". What impact does that have here, where we've been told a particular TRUE claim is not of interest? Nada! So what that some untrue things are not interesting? This true thing still might not be.

When we negate E, though, we get "truth IS sufficient for scientific interest". That destroys the argument - a tautology MUST be of interest, because it's true. Since the negation of E wrecks the original argument, answer E must be an assumption of the argument.

If that doesn't clarify it sufficiently for you, I've got one more approach that might also help, so let me know how that went for you. Study that special, powerful technique, and assumption questions could become the easiest ones on the test for you.

Good luck!

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