You're listening to Brainson, where we're serious about being curious.

Brainson is supported in part by a grant from the National Science Foundation.

So Mary, what would the opening of Brainson sound like if it were opposite day right now?

Maybe something like this?

You are not listening to Brainson. This is not Molly Bloom, and we are not curious about anything.

That tree over there? Boring. My phone? I don't care how this thing works.

That dog, it is not super cute, and I'm definitely not interested in finding out why it wants to smell

all the things. Nope. You want a mystery sound? Too bad.

Here's a sound of me turning off this microphone because there are no questions to answer,

and no one interesting to talk to. Bye.

You know, I'm not sure I'd want to listen to that show. Well, at least the episodes would be really short.

Luckily, it's not opposite day here on Brainson, but opposite day is on our minds.

We're going to talk all about logic and paradoxes today, and we're going to have some fun

tying our minds in knots. Keep listening.

You're listening to Brainson from American Public Media, and here with me today is 15-year-old Mary

Moore from Lake Shore, Minnesota. Hi, Mary. Hi, Molly. And this episode was inspired by a question

that you sent into us. Let's hear it. I'm wondering how I can determine whether today is opposite day or not.

When I asked if today is opposite day, my teacher said no. If it is opposite day, and he says no,

then it really must be opposite day. But if it isn't opposite day, his answer would be the same.

Please tell me if you're out of this paradox.

Since, surely, Mary Moore. That is a great question. So, Mary, what made you think of this question?

Well, we play opposite day a lot at our house. We just like,

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