Logical ReasoningDifficulty: Hard

PT127 S1 Q19 Explanation

Editorialist: Some people argue that

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

TopicsNecessary Assumption

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Stimulus

Editorialist: Some people argue that we have an obligation not to cut down trees. However, there can be no obligation to an entity unless that entity has a corresponding right. So if we have an obligation toward trees, then trees have rights. But trees are not the we have no obligation not to cut down trees.

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
19.

The editorialist’s argument depends on assuming which one of

Answer choices

  1. Trap19% picked this

    If an entity has a right to certain treatment, we have an obligation to treat

    Reversed Logic Out of Scope: certain treatment The wording of "certain treatment" doesn't really match up with anything, so this feels fishy from that. But if we closely inspected it, we'd see that it's reversing the logic of something we were told. We were told if there's an obligation, then it has a right This answer is saying if it has a right, then there's an obligation

  2. Reversed Logic8% picked this

    Any entity that has rights also

    This has the same problem as (A). We were told if there's an obligation, then it has a right This answer is saying if it has a right, then there's an obligation It is also getting confused in the sense that the argument was talking about whether we have an obligation to X, based on whether X has rights. This rule is about whether X itself has obligations, so in addition to reversed logic, it's also just distorting what we were even talking about.

  3. Out of Scope: conscious entities11% picked this

    Only conscious entities are the sort of things that can

    This is probably tempting if we're trying to play Mind Reader and explain the backstory behind the premise that "trees are not the sort of things that can have rights". But the author's rationale for that does not have to be that "only conscious entities can have rights". In fact, the author may believe that dead people (not conscious) still have rights. Maybe she thinks they have the right to not have their graves robbed, or to not have their likeness used in commercials without their relatives' permission.

  4. Correct60% picked this

    Avoiding cutting down trees is not an obligation owed to some entity

    Why this is right

    Whenever we're doing Necessary Assumption and we see an answer using the ruling out verbiage of "not / no", we should consider it, since so many correct answers are written that way. If we negate this, does it weaken? Avoiding cutting down trees is an obligation owed to some entity other than trees. Heck yeah, it weakens! In this case, it basically contradicts the conclusion! (it doesn't need to do that to be correct; it just needs to weaken more than any other answer's negation would weaken). This negation starts to sound like our counterarguments from before - we have an obligation not to cut down trees, because of the obligation owed to our nextdoor neighbor, who wants to keep her tree, or because of the obligation owed to future generations of humans, who want a livable climate. If we're not using the Negation Test to see why this is the correct answer, we would be thinking that this addresses the gap we found: if we don't have an obligation to trees not to cut them down, then we have no obligation to not cut them down, because avoiding cutting down trees isn't an obligation owed to any other sort of entity.

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

  5. Weakens2% picked this

    One does not always have the right to cut down the trees on

    According the author's conclusion, we should be able to cut down any tree we want. We have no obligation not to cut down trees. So this answer actually seems to be undercutting the author's conclusion, because it is placing limits on our right to cut down trees.

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