Later he could not recall the details of this dream, but that rush of piercing joy he did not forget. He had never known anything like it; so certain was its assurance of permanence, like one glimpse of a light that shines steadily, that he never thought of it as unreal though it had been experienced in dream. Only, however reliable there, he could not reattain it either by longing for it or by the act of will. He could only remember it, waking.

— Ursula K. Le Guin, The Dispossessed, Harper & Row, Ch. 2, 1974