How can things like "individual persons" exist?

[Aloysium]

How can there be a “you” alongside “me?” I came up with this thought when I was very little (about 4 or 5) and I was very confused. I tried to ask this to my mom, but with the vocabulary and verbal skill of a 5 year old, it was fruitless. She just said that I was being selfish, and to this day I still can’t tell what she thought I meant. . .

You should have asked your grandpa or grandma. Having more time, they can listen better.

“How can there be a you alongside me?”
“You aren’t along side me; you are in my heart. And I hope I am in yours.”
“But why, Nonno?”
“If you weren’t you, how could I love you? Who would I hug?”