Foil
Character Role Analysis
Jan and Stormgren
Foils are all about characters contrasting each other. If you think of each character as a white room, then his or her foil is the contrasting color that gives the room a little something extra, really making the whole ensemble "pop." Or something like that. It's not like we're interior decorators or anything.
Anyway, Jan and Stormgren are foil pairing number one. Both are willing to disobey the Overlords for their own personal gain—Stormgren wants to find out what Karellen looks like; Jan wants to go into space—but how they're interested and willing to do so differs.
Stormgren is only willing to disobey the Overlords in keeping with Karellen's plans. He wants Karellen to succeed in crafting the World State, so he keeps what he learns about the Overlords a secret even when talking with the news reporter years later (4.156-157).
Jan, on the other hand, doesn't care about Karellen's plan. He goes out of his way to rebel against the ruling that no human shall go into space and gives little thought to how it will affect the Overlords' plans for humanity. If anything, he might resent the plan.
Jeff and George
Another foil pairing we have is George and his son, Jeff. George is no explorer and has "no wish to face whatever lurked in the unknown darkness, just beyond the little circle of light cast by the lamp of science" (16.7). Jeff, however, is an explorer. He enjoys swimming out deep into the lagoon and searching sunken ships for undersea treasures. By comparing George with his son, we can see the qualities that make Jeff and his generation more applicable to the Overmind than their parents, eking out a little knowledge as to what the Overmind is.