My two oldest children are trying to decide whether the cat Tidus treed outside our kitchen window is a boy or a girl.  From their earnest expressions it is obvious to the passer-by that this is vitally important information.  After discussing for a short time, my son definitively states:

"It’s a boy."  Hops down, sure of himself, and thus ending the conversation.

"Why do you think it’s a boy?"

"Mom," (as exasperated in my witlessness as a teenager) "It’s a boy!"

"But how do you know?"

Knowledgeably and with hands fluttering about his own short hair: "Because girls have all tangly hair!"

"Oh." (Remembers giving the required explanation of my strange habit of brushing my hair every morning to our buzz cut boy.  "When girls have long hair it gets tangled.")

Soon, they are putting on shoes and coats. 

"What are you doing?"

"Mom, we’re going to go talk to the kitty a minute."

Ok… "Why?"

"Because…because, I think that it’s our kitty." (We don’t actually have a cat… yet.)

Lithany chimes in: "That kitty is a she."

"Why do you think that?"

"Because it is Lucia!" (EVERYTHING’s name is Lucia.) 

The ultimate proof, dear friends, on why logic is an important part of schooling!