and the moon passes over the sun and nothing changes and nothing is learned because you have lost your bucket and shovel and no longer care. What if you regain the surface and open your sack and find, instead of treasure, a beast which jumps at you? Or you may not come back at all. The winches may jam, the scaffolding buckle, the air conditioning collapse. You may glance up one day and see by your headlamp the canary keeled over in its cage. You may reach into a cranny for pearls and touch a moray eel. You yank on your rope; it is too late.