"I am aware," Daneel observes, "which would imply this is my dream, but this does not resemble any place I have seen. Nor should I be able to dream."

He's going through the problem rationally, or at least as rationally he can be in a dream. He's not coming to any sensical conclusions, either. When he was human, he dreamed of people he knew, places that were familiar. He doesn't know the man in front of him, nor why he would imagine him as a boy.

"Is this your dream?" Strange, impossible, but he can't rule it out either.