I wasn't talking about an adult. [ He was talking about a 14 years old boy. Perhaps a teenager is no longer the age Jack considers to be a child, but, well.

But even so, doesn't it justify why an adult would no longer care for imagination? ]

Perhaps. But after a while., what you'd think to be an easy thing to realize, it's not. It becomes blurred and it's difficult to even think "That's it. That's what will make me happy".