Logical ReasoningDifficulty: Hard

PT110 S3 Q17 Explanation

Zoologist: Animals can certainly signal

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsNecessary Assumption

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Stimulus

Zoologist: Animals can certainly signal each other with sounds and gestures. However, this does not confirm the thesis that animals possess language, for it does not prove that animals possess the ability to to concrete objects or abstract ideas.

What this question is testing

Necessary Assumption

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
17.

Which one of the following is an assumption on which the zoologist’s

Answer choices

  1. Out of Scope: entertain abstract ideas2% picked this

    Animals do not have the cognitive capabilities to entertain

    This argument is about whether or not a certain thing proves that animals possess language, which is not the same as discussing whether or not they have the capacity to have abstract thoughts. It's also useful to remind ourselves that this author is not claiming / assuming / concluding that animals don't have language. She is only saying "This piece of evidence doesn't prove X, because it doesn't prove Y". She might fully believe that animals do possess language and simply be arguing that "the way we prove that is NOT by pointing out that they can signal each other with sounds and gestures".

  2. Out of Scope3% picked this

    If an animal’s system of sounds or gestures is not a language, then that animal is unable

    Out of Scope: unable to entertain ideas Bad Trigger Match This answer is offering an incredibly strong universal claim (conditional rule), no part of which repeats any concepts from the Premise or the Conclusion. When we see conditional answers on Necessary Assumption, we can look at them (in original and contraposed form) and see if either form accurately captures a reasoning move that the author made. animal's system of animal is unable sounds / gestures is ? to entertain not a language abstract ideas able to entertain ? system of sounds abstract ideas is a language Neither form matches the argument. The argument didn't say, "Since the sounds these animals make isn't a language, we can conclude they cannot entertain abstract ideas". And it didn't say, "Since these animals are able to entertain abstract ideas, we can conclude that their system of sounds is a language".

  3. Actual vs. What it Proves29% picked this

    When signaling each other with sounds or gestures, animals refer neither to concrete objects

    Yikes, this is a mean trap answer. I would have been very tempted by this (as it essentially matches one of my two guesses). It's wrong because it deals with what is actually the case, when the author's conversation is only about what X does or doesn't prove. Suppose we were to say, "the fact that Megan didn't respond to Gabe's texts doesn't prove that she's mad at him". Are we assuming that Megan isn't mad at him? No, we're just saying that you can interpret that "non-response" from Megan in different ways (maybe she's mad / maybe she lost her phone / maybe she's stuck in a work meeting). Thus, not responding to texts doesn't prove she's mad. This author is similarly only talking about what stuff does or doesn't prove, not what is actually the case. Try negating this answer -- when the animals are signaling each other, they are referring to concrete objects or abstract ideas. The author could say, "That's great! Maybe they really have language then. All I was saying was that their ability to signal each other doesn't prove that they're referring to concrete / abstract things. I wasn't saying it's impossible that it refers to concrete / abstract things."

  4. Correct64% picked this

    If a system of sounds or gestures contains no expressions referring to concrete objects or abstract ideas, then that

    Why this is right

    This is just showing that basic assumption we first derived, "It ain't language, unless you're referring to concrete objects or abstract ideas". Because of this assumption "in order to be a language, you must have some sounds or gestures that refer to concrete / abstract things", the author can say "If X doesn't prove that there are sounds or gestures that refer to concrete / abstract things, then X doesn't prove that something is language". That doesn't mean that X alone would prove something is language, but you can't prove that something is Z until you've established that it meets all the necessary criteria of being Z.

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

  5. Out of Scope2% picked this

    Some animals that possess a language can refer to both concrete objects

    Out of Scope: animals that possess Actual vs. What it can prove This answer is again dealing with whether it's factually true that some animals do or don't have language. The argument is only caring about what type of evidence can / can't prove that, not about whether it's true or not. The author doesn't need to assume that any animals possess language. Finally, the author technically wouldn't need to assume that a language can refer to both concrete and abstract. The argument makes it seem like a requirement that a language refers to concrete or abstract.

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