The principle of bivalence states that every statement is either true or false, and nothing else. It's like a light switch - it can only be off or on, nothing else! This means that when we make a statement, it has to be one or the other. For example, if I say "I am wearing a red shirt," that statement has to be either true or false - I either am wearing a red shirt or I'm not. It can't be anything in between!