LR Question 14 Explanation
QUESTION TEXT: Certain methods of creating high-quality counterfeit…
QUESTION TYPE: Sufficient Assumption
CONCLUSION: Prevent Counterfeiting ➞ some hard images
REASONING: No evidence is provided, apart from the contextual statement that some counterfeiting involves measuring images.
ANALYSIS: Normally, on sufficient assumption questions, you can draw the conclusion, fill in the evidence, and then spot the gap. However, some arguments literally give no evidence for their conclusion. In this case, all we have is this conclusion:
Prevent Counterfeiting ➞ some hard images
If you split it apart, it looks like this: PC HI
To prove this correct, we just need a statement that fills that gap:
- Conclusion: Prevent counterfeiting ➞ can’t copy images
- Contrapositive: can copy images ➞ can’t prevent counterfeiting
This might seem like circular reasoning, but it’s not. It’s like saying “I think pandas eat bamboo”. And then the sufficient assumption would be “The encyclopedia says that Pandas do eat bamboo”. It’s the same statement….but the first one was unfounded, whereas the second one provides proof.
Note: It seems like the first sentence is evidence. Indeed, I even listed it in the reasoning section, above. But it’s not a conditional that connects to either part of the conclusion, and so it can’t help us prove the argument. That means we ignore it.
___________
- This doesn’t help prove we need better images. Maybe sophisticated copying technology can copy better images too.
- CORRECT. The conclusion was just two facts. This connects those facts. You have to take the contrapositive to see how it leads to the conclusion.
Answer: Measured ➞ Can counterfeit
Contrapositive: Can’t counterfeit ➞ Can’t measure
Note that the terms don’t exactly match the terms of the conclusion in the stimulus. Who cares? It’s plain that they’re pretty much the same thing. If you make an image “very difficult or impossible” to measure, then that’s about the same as saying people won’t be able to measure them. And “no impediment to being replicated” = can counterfeit. - So? Counterfeiting technology could still be good enough. This doesn’t prove that hard images are required to prevent counterfeiting.
- So? We’re trying to prove that hard images are necessary. This answer merely shows they are rare.
- It’s not clear how this affects the argument. If the new designs aren’t images, then this contradicts the argument. If the new designs are images, then it’s still not clear they’re an essential cause.
More Resources for Sufficient Assumption Questions
- Conditional Reasoning Article: Learn about conditional statements.
- LR Diagrams Guide: Learn how to draw LR diagrams.
- Intro to Conditional Reasoning: Learn conditional reasoning basics.
- Intro Course lesson: This intro course lesson covers Sufficient Assumption questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers sufficient assumption questions.
While B is the best answer, i think it isn’t a great answer because “very difficult or impossible” doesn’t guarantee the conclusion can be drawn.
If it’s “impossible” to measure accurately, yes the conclusion can be drawn.
But if it’s just “very difficult” this doesn’t guarantee that it cannot be measured accurately, and thus does not guarantee that production of HQ counterfeit bank notes is prevented.
I see what you’re getting at, but I think your confusion is about what the argument is trying to prove and what a sufficient assumption is supposed to do.
The conclusion says: If prevent counterfeits -> images very difficult or impossible to measure accurately. That’s not claiming that “very difficult” guarantees prevention – just that it’s a necessary condition if prevention is the goal.
Answer choice B tells us that once you measure images accurately, there’s no other barriers to creating a counterfeit. So if accurate measurement is all it takes to create a counterfeit, then the only way to prevent it is to do exactly what the conclusion says: make it very difficult or impossible to measure accurately.
Even if “very difficult” doesn’t make counterfeiting impossible for everyone, it still helps prevent some successful attempts. That satisfies what the conclusion is saying: that making some images very difficult or impossible to measure is a necessary step in prevention.
So B bridges that gap. It tells us that if people can measure, they can counterfeit – meaning that the only way to stop them is to make measuring either impossible or extremely hard.
Hope that helps, let me know if you have more questions!
Edit: Another thing to add is that the LSAT uses dictionary definition of words. The definition of prevention is to stop something from happening, and the ordinary use of prevention in this context is when measures are implemented to reduce the risk of something. So “very difficult” still satisfies the definition and ordinary use of prevention, because prevention doesn’t necessitate total elimination.