[commenter23]

Nit: The pigeonhole principle is exactly the opposite of "only one object being in one location at a time".

It says that if you have m pigeons and n holes, and m > n pigeons, at least one hole is going to have two pigeons in it.

[coldtea]

It's not the same pigeon that's twice in the same hole though, so it's not "exactly the opposite" -- just orthogonal.

[kjhughes]

You're right. I've removed the erroneous reference so that it doesn't detract from the rest of the post. Thank you.