Logical Reasoning

PT130 · S3 · Q18 It was once thought that pesticide TSX-400

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

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

It was once thought that pesticide TSX-400 was extremely harmful to the environment but that pesticides Envirochem and Zanar were environmentally harmless.

Conclusion

If the studies are accurate, either E and Z should be banned or TSX should be legal.

Evidence

We banned TSX, thinking that it was terrible while E and Z were okay. But these new studies say that E and Z are worse than TSX.

Evaluation

This is similar to the real world debate about whether or not cannabis should be legal. Alcohol and tobacco are legal, and they have more harmful effects than cannabis does. So consistent policy would either say all three should be illegal, or that cannabis should join the ranks of the legal. It wouldn’t make any sense for the mildest of the three (in this case TSX) to be the only one that is illegal.

Goal

We need a principle that argues in favor of consistency. We shouldn’t have the least harmful thing be illegal while the more harmful things are legal. Either make them all legal or make them all illegal.

18.

Which one of the following principles, if valid, most helps to justify the argumentation?

  1. Two pesticides should not both

    Bad Conclusion Match

    If we know that E and Z are more harmful than TSX, this rule tells us that they shouldn’t all be legal. But the author’s conclusion is allowing for them to all be legal. So this doesn’t match the author’s argument.

    13% picked this

  2. Two pesticides should both be

    Bad Conclusion Match

    If we know that E and Z and TSX are harmful to the environment, this rule tells us that they shouldn’t all be legal. But the author’s conclusion is allowing for them to all be legal. So this doesn’t match the author’s argument.

    4% picked this

  3. Two pesticides should both be

    Bad Premise Match

    This says “If at least one of these is not harmful to the environment, then they can’t all be illegal”. All three of the pesticides are harmful, so this rule is useless as it is inapplicable to the pesticides being discussed.

    8% picked this

  4. Correct

    One pesticide should be legal

    Why this is right

    This says, “If A is legal and B is illegal, then A must be less harmful than B”. The contrapositive, “If A is at least as harmful as B, then you can’t have A be legal and B be illegal.” This matches well with the argument: If E and Z are at least as harmful as TSX, then you can’t have E and Z be legal while TSX is illegal.

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

    66% picked this

  5. One pesticide should be legal

    Bad Premise Match

    This says, “If A is harmless and B is harmful, then A should be legal and B should be illegal”. We don’t have any harmless pesticides being discussed here, so this rule is inapplicable to our situation and thus useless.

    9% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free