Adventure
There's a structural trick hiding across a century of adventure narratives: the protagonist doesn't seek the sky so much as get expelled from the earth. Rob in Baum's *The Master Key* finds the air "a veritable refuge" only after nearly dying on the ground; Teresa in Brin's *Earth* launches atop a volcanic plume in a shuttle that cannot fly, and feels joy; Max loses everything at ground level and only survives by commandeering Jedediah's plane from inside a mesa. Even Milo in *The Phantom Tollbooth* doesn't choose to leave — the tollbooth appears, and suddenly "what had started as make-believe was now very real." The pattern inverts the adventure myth: these aren't stories about the call to adventure, they're stories about the ground refusing to hold you. Sagan almost names it — "humans experience weightlessness as joy" — but misses the darker corollary that Dubos catches: we are earthbound forever, which means every flight is also a kind of exile. Adventure, in the graph, sits one edge from Survival for a reason. The thrill is inseparable from the eviction notice.