ELI5: Explain Like I'm 5

Frege's theorem

Okay, kiddo, let me explain Frege's theorem in simple words. Do you know what numbers are? Yes, like 1, 2, 3, and so on. Cool! Now, do you know what symbols are? Like a plus, minus, or multiplication sign. Great job!

Frege's theorem is about how we use symbols to talk about numbers. Imagine you have two sets of objects, like apples and oranges. You can count how many apples or oranges you have, right? Now, what if you want to compare the number of apples to the number of oranges? How can you do that? That's where symbols come in.

Frege's theorem says that we can use symbols like "=" or "≠" (which mean "equal" or "not equal") to compare numbers. We can also use symbols like "+" or "-" to add or subtract numbers.

But here's the catch: we have to make sure that each symbol we use means the same thing every time we use it. For example, if we say that "1 + 2 = 3", we can't suddenly start using "+" to mean something else, like "divide". Otherwise, everything we said before would make no sense.

That's why Frege's theorem is important. It helps us understand how symbols work in math and how we can use them to talk about numbers in a clear and consistent way. Does that make sense, kiddo?