But you were like a blank page when they found you, weren't you? I find it hard to see how you would remember feelings when you have no memories of ever being human. And I told you, having a best friend, hurting when you think they are gone forever, those things are done with a heart. If he maintains that they aren't real...

[A pause, when he continues there's a sneer in his tone.]

Then your friendship with him isn't real either, and it's just you "remembering" what's like to have a friend.