LSAT 151 | Section 4 | Logical Reasoning: Q13

LR Question 13 Explanation

QUESTION TEXT: Legislator: My colleague says we should reject this…

QUESTION TYPE: Flawed Reasoning

CONCLUSION: We should approve the act.

REASONING: My opponent’s motives for opposing it are shifty.

ANALYSIS: This is a classic ad hominem. Rather than reply to the actual argument, the legislator has attacked her opponent’s motives. She should have justified the argument about deterring investment instead.

Incidentally, the opponent isn’t necessarily a hypocrite. Everything in policy involves tradeoffs. In some cases, you might accept a small decline in investment if it had major benefits. But it’s possible this law has a major decline in investment for tiny benefits. So a politician could support investment in some circumstances and restrict it in others, without being incoherent.

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1. This would be a highly unusual flaw. It is not describing ad hominem. It’s describing something different.
   Example of flaw: This lawyer is very messy and disorganized. So clearly, their professional viewpoint is that the law should be messy and disorganized.
2. CORRECT. This describes a version of an ad hominem flaw. Really, the legislator failed to make any argument at all. Instead they only attacked their opponent’s motives. “The grounds” refers to the claim that the bill will decrease investment: the legislator gave no argument about that.
3. The legislator didn’t do this: they said nothing about how they expect most people to vote. Actually presuming your opponent was in the minority would be a very different flaw. And to do so “without justification” means literally no justification. It’s the equivalent of walking into a room, looking at someone and saying “Hey, you’re opposed to skyscrapers, right?” without bothering to check their position on the issue.
   Example of flaw: I just got to the legislature and haven’t asked anyone what they think. You all disagree with my opponent though, right?
4. The legislator said nothing about voters or the public. When she said “vote”, she was referring to how members of the legislature should vote.
5. Actually, I’d say the legislator did consider this sort of thing. She said her opponent’s reason “must not be very persuasive”, because the opponent wouldn’t say their presumed real reason out loud. If their actual reasoning was merely “my constituents oppose it”, that indeed wouldn’t be all that persuasive. (In other words, the legislator considered that her opponent may have had a variety of reasons, none of them publicly persuasive. If “my constituents oppose it” were persuasive, the opponent would have said it directly)