Oh. Ned hadn't really foreseen this complication. He ought to have, and his own oversight helps him to understand, more immediately and deeply, Charlie's earlier frustrations at everyone being from a later time period than himself.

And now he has to figure out how to explain what Daneel is to Charlie, without sounding condescending, but without confusing him either.

"In your time, and my time, yes. By his time, it's science, but not the fictional kind. He's..." Where does Ned even begin, "He wasn't born, like you or I were born, or like a cat or a dog is born. He was made. Designed and put together and activated, by scientists, using very advanced technology. From the outside he looks exactly like a human being, because... that was the whole point. But underneath he's a bit different. You and I are organic." No, that's probably not going to be helpful. Ned changes tactics, "Basically, we're mostly made of meat. But he's mostly made of metal. He doesn't have to do stuff like eat or sleep because he has a different sort of power source."

There are other nuances, important ones, but he's starting with the basics here. They can get to postironics later, when Charile's ready, and if he's interested.