LSAT 108 | Section 2 | Logical Reasoning: Q21

LR Question 21 Explanation

QUESTION TEXT: The experts who now assure us that …

QUESTION TYPE: Flawed Parallel Reasoning

CONCLUSION: Genetically engineered plants will also be harmful.

REASONING: Experts claim they’ll be harmless, but they were wrong about non-native plants before.

ANALYSIS: Same people were wrong before, so they’re wrong now. The experts made a bad prediction about non-native plants, so they must be wrong about genetically engineered plants too now.

That’s bad. People can be wrong about one thing and right about another. The two issues may be completely unrelated. At most, their past error gives us a reason to be skeptical, not to conclude the opposite prediction is true.

Past mistakes don’t prove current claims are false.

___________

1. This just notes that the same people hold two contradictory positions that aren’t compatible. It doesn’t infer that someone’s current prediction is false because they were wrong before.
2. This relies on the fact that the last film was good to conclude that the new one will be good too. So it’s a flawed “past success → future success” move. But here, the critics were supposedly right before and wrong now. In the stimulus, the experts were supposedly wrong both times.
3. CORRECT. The economists were wrong before, so their current prediction must be false and the opposite of their current prediction is true. It’s the same as the stimulus.
4. This is a recommendation about how parents should respond to children’s requests. It doesn’t rely on experts making repeated predictions.
5. So if there’s shortages, it won’t be because experts predicted them. That’s attacking a causal relationship between predictions and events. It’s not inferring that a current prediction is false because experts were wrong before.