Unit 8 · Detecting Reasoning Errors

Red Warning Light — Rule Scope Error

Lesson 29 of 34

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A flashing red light warns that the processor is starting to overheat. Yifan concludes no flashing means everything is fine. Ria concludes a continuous light means it has overheated. Both are wrong — the rule only defines what the flashing signal means, and nothing else.

Chapters

0:00Introduction
0:22Question
1:05Strategy
1:44Step 1: Rule scope + Yifan — inverse error
2:48Step 2: Ria — conclusion from an uncovered state
3:47Correct answer

Question

Whenever the red light on the side of Yifan's computer is flashing on and off, it means that the processor is starting to overheat.

Yifan said: "The red light isn't flashing at the moment, so the temperature of the processor must be fine."

Ria said: "No, that's not right. The light is on continuously – that must mean that the processor has already overheated!"

If the information in the box is true, whose reasoning is correct?

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