(At LessOnline)
You come to talk to someone you hadn’t noticed before. After some chitchat, she tells you she’s psychic and can read minds.
- Oh really?
It strikes you as a ridiculous claim to make, especially at a rationalist event.
- Is there any way you can prove your claim?
- Sure there is. Think about a number.
You think of 43.
- You thought of the number 43.
She wasn’t even asking for confirmation, like magicians sometimes do (“Is this your card?”). She seemed to know she was right.
- … Wait! This is the old xkcd trick: you try it multiple times, each time with the same confidence, until it works. I’m just the 1/100th guy. (Cf. xkcd.com/628)
- That might be it. How about I guess the next one?
- The… you think you…
- 27.
- …
- Now the odds are 1 in 10.000. I sure must have done this trick many times at parties!
There must be an explaination. You just cannot think of one.