Solitude (n.) becomes loneliness when, all by myself, I am deserted by my own self.
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Solitude (n.) is when the thinker is least alone, said Cato — never more active than when doing nothing.
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Solitude (n.) is being by myself, in company with my self — two-in-one — whereas in loneliness I really am one, deserted by everyone else.
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Solitude (n.) is the condition in which one is never less alone — never less alone than when by oneself, never more active than when doing nothing.
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Solitude (n.) can rescue the lonely, as when Nietzsche at Sils Maria found that "at noon, One became Two" and Zarathustra came, the guest of guests.