Joke's on you! Humans will be extinct by 2531. Maybe by 2031 if Trump becomes president again.

That doesn’t contradict the original statement

But it does though

“Every person in Japan will be called Sato.”

In formal logic, this is equivalent to
“There is no person in Japan not called Sato.”

Since there are no people, no one is not called Sato, and therefore every person is called Sato. Every person is also called Steve. Or Klaus.

Since there are no people, no one is not called Sato, and therefore every person is called Sato.

Uh… No? 🤨

∀P∈{X | X lives in Japan} : P is named Sato

using De Morgan’s negation rule this is equivalent to

⇔ ∄ P ∈{X | X lives in Japan} : P is not named Sato

Since {X | X lives in Japan} = ∅ is the empty set, such a person P can by definition not exist. Which means, the first statement is true. If no person lives in Japan, that means every person living in Japan is named Sato.