How Does Argument Schemes: Modus Tollens Work?

Modus Tollens is a kind of logic puzzle that helps us figure things out by looking at what doesn’t happen.

Imagine you have a toy robot that says, “If I get enough batteries, I will dance.” That’s like saying: If A happens, then B happens.

Now suppose the robot doesn’t dance. What does that tell you? It probably means it didn’t get enough batteries! So if B doesn’t happen, then A probably doesn’t happen either.

Like a Broken Swing

Think of it like this: You have a swing in the park. If someone pushes it, it goes high. That’s like saying: If pushed (A), then swings high (B).

One day, you look at the swing and see that it doesn’t go high. So you think, maybe no one pushed it! That’s Modus Tollens in action: If B didn’t happen, then A probably didn’t either.

It's like a detective clue. If something usually happens when another thing happens, and now the first thing didn't happen, then maybe the second thing didn’t happen too. Simple, fun, and logical!

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Examples

  1. If it rains, the ground gets wet. The ground is not wet, so it did not rain.
  2. If a cat is hungry, it will meow. The cat didn’t meow, so it isn’t hungry.
  3. If you study, you pass the exam. You failed the exam, so you didn’t study.

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