Photo by futureatlas.com
Here are even more amazing paradoxes to baffle your students: Buridan’s Bridge, the Bootstrap Paradox, and the Barber Paradox.
Buridan’s Bridge stars Plato and Socrates and was created sometime in the 1300s.
- Socrates wants to cross the bridge. Plato is standing on it.
- Plato says: Make a statement. If it’s true, you may cross, but if your statement is false, I’ll throw you into the river.
- Socrates says: You’ll throw me into the river.
The paradox is:
- If Plato throws him in the water, he broke his own rule since now the statement is true. And he promised to let him pass.
- If Plato lets him pass, he has broken his own rule also since the statement is false. And he promised to throw him in.
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There are several bootstrap paradoxes, and they all have to do with Time Travel, which of course opens up incredible paradoxes.
In this one, a man receives a visitor. It’s himself from the future… with the plans for a time machine! It takes years, but the man uses the plans to build the time machine then travels back and gives himself the plans.
The paradox is: was the time machine ever actually designed, or were these plans just passed down infinitely?
In the Barber Paradox, there is one barber in a town. He follows this one rule: he shaves all men in town, but only if they don’t shave themselves.
So, does the barber shave himself?
- If he shaves himself, then he violates the rule since he only shaves those who don’t shave themselves. But he does shave himself.
- If he doesn’t shave himself, then he violates the rule since he claims to shave all men in town as long as they don’t shave themselves. And he doesn’t shave himself.