Ursula K. Le Guin

     "I never thought before," said Tirin unruffled, "of the fact that there are people sitting on a hill up there, on Urras, looking at Anarres, at us, and saying, 'Look, there's the Moon.' Our earth is their Moon; our Moon is their earth."

    "Where, then, is Truth?" declaimed Bedap, and yawned.

    "In the hill one happens to be sitting on," said Tirin.

em The Dispossessed, London: Gollancz, 2002, p. 37.