Logical ReasoningDifficulty: Medium

PT102 S4 Q18 Explanation

Obviously, we cannot in any real

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

TopicsSufficient Assumption

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Stimulus

Obviously, we cannot in any real sense mistreat plants. Plants do not have nervous systems, and having a necessary to experience pain.

What this question is testing

Sufficient Assumption

Conclusion

The author is saying: plants can't be mistreated.

Evidence

The reason: plants don't have nervous systems, and you need a nervous system to feel pain. So plants can't feel pain.

Evaluate

The argument gets us to "plants can't feel pain." But the conclusion is "plants can't be mistreated." Those aren't the same thing unless we assume mistreatment requires the ability to feel pain.

Think of it like this: imagine someone arguing That only works if you assume hearing is required for being insulted. Without that bridge, the argument has a hole.

Goal

The right answer needs to bridge "no pain" to "no mistreatment" — basically: only things that can feel pain can be mistreated.

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

The question
18.

The conclusion above follows logically if which one of the following

Answer choices

  1. Reversal / Negation10% picked this

    Any organism that can experience pain can

    This says "any organism that can experience pain can be mistreated" — pain → mistreated. We need the reverse: mistreated → pain. The argument tells us plants can't feel pain. To conclude they can't be mistreated, we need pain to be a requirement for mistreatment, not a guarantee of it. (A) gives us an arrow pointing the wrong way and so does not make the conclusion follow.

  2. Premise Support9% picked this

    Only organisms that have nervous systems can

    "Only organisms that have nervous systems can experience pain" simply restates a premise already given in the stimulus ("having a nervous system is necessary to experience pain"). It does not bridge the gap between pain and mistreatment, which is where the argument has its missing link. Adding this assumption changes nothing.

  3. Reversal / Negation4% picked this

    Any organism that has nervous system can

    This says any organism with a nervous system can experience pain — nervous system → pain. The stimulus gives us nervous system as a necessary condition for pain (no nervous system → no pain), not a sufficient one. And even if (C) were granted, it still doesn't connect pain to mistreatment. The argument's gap is between pain and mistreatment, and (C) does nothing about that gap.

  4. Correct70% picked this

    Only organisms that can experience pain can

    Why this is right

    This is the bridge. "Only organisms that can experience pain can be mistreated" means: if you can be mistreated, you must be able to experience pain (mistreated → pain). Combined with the premise chain — plants have no nervous system, so plants cannot feel pain — we get: plants cannot feel pain, therefore plants cannot be mistreated. With (D) added, the conclusion follows logically.

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

  5. Reversal / Negation6% picked this

    Any organism that has nervous system can

    This says any organism with a nervous system can be mistreated — nervous system → mistreated. The argument needs the contrapositive direction: mistreatable → can experience pain (or, equivalently, mistreatable → has a nervous system). (E) tells us nervous systems make mistreatment possible, which is sufficient instead of necessary — the wrong direction. It does not let us conclude that plants (which lack nervous systems) cannot be mistreated.

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