Who is Axiom of Extensionality?

The Axiom of Extensionality is like saying two toy boxes are the same if they have exactly the same toys inside, no more, no less.

Imagine you and your friend each have a box of crayons. If both boxes have exactly the same colors, say, red, blue, yellow, then even if one box is bigger or has a cooler design, you can still say they’re basically the same when it comes to what’s inside.

Extensionality means that what's inside matters most. If two things have the same contents, they're treated as equal, like how your lunch bag feels just as full whether it's a regular bag or a superhero-themed one.

Think of it this way: if you and your friend both have a set of favorite toys, and you both have exactly those same toys, no extra ones, no missing ones, then even though the bags might look different, they're still just as good. That's the Axiom of Extensionality in action!