What metaphors are used in Childhood's End by Arthur C. Clarke?

Rashaverak uses this analogy to try to explain telepathy to George. More generally, this is a way to metaphorically understand the connection between Jean and Jeff, and the Children's evolution.

"Imagine that every man's mind is an island, surrounded by ocean. Each seems isolated, yet in reality all are linked by the bedrock from which they spring. If the oceans were to vanish, that would be the end of the islands. They would all be part of one continent, but their individuality would have gone. Telepathy, as you have called it, is something like this" (151) (Metaphor)