Completeness (logic)
Completeness in logic means that we can use a certain set of logical rules (like "if A is true and B is true, then A and B together are true") to prove any statement we want to be true or false.
To explain like you're 5:
Let's say you have a puzzle with a bunch of pieces. Completeness is like having all the pieces you need to complete the puzzle. No matter what picture you want to make, you have all the right pieces to do it.
In logic, the "pieces" are the logical rules we use to prove things, and the "picture" is the statement we want to prove as true or false. If your set of logical rules is complete, you have all the pieces you need to solve any puzzle - or prove any statement - you want.
To explain like you're 5:
Let's say you have a puzzle with a bunch of pieces. Completeness is like having all the pieces you need to complete the puzzle. No matter what picture you want to make, you have all the right pieces to do it.
In logic, the "pieces" are the logical rules we use to prove things, and the "picture" is the statement we want to prove as true or false. If your set of logical rules is complete, you have all the pieces you need to solve any puzzle - or prove any statement - you want.