Something like that. It's like... [How can he put this?] Like people are kind of two parts: there's the body, which houses the soul--like the personality? [For lack of a better way to explain it. When he lost his heart, he was still mostly the same person, he just couldn't feel anything.] And then there's the heart, which houses the emotions. So if you take them apart, you just get monsters that are less than people. One is all emotion, seeking more hearts to feed itself, and the other is just an empty husk, seeking hearts to replace the one it lost.

[That's what he'd been: a monster. That's what they had all been. He wasn't going to romanticize it. But Asami didn't need to know that part.]

Anyway. Ansem camped out in his lab in the basement of the castle and spent all his time trying to quantify the heart. I guess he finally figured out you couldn't really do that, though. I don't think you can just put hearts in a nice neat box that explains each and every one--they're too different, too complicated.