— Carl Sagan, Contact
This is a paraphrase of Sagan quoting Thomas Carlyle: "A sad spectacle. If they be inhabited, what a scope for misery and folly. If they be not inhabited, what a waste of space."
Sagan delivered this quote during the symposium on "Life Beyond Earth and the Mind of Man", held at Boston University (20 November 1972), published in Life Beyond Earth and the Mind of Man (1973) edited by Richard Berendzen; Life Beyond Earth and the Mind of Man (1975) National Archives video http://www.youtube.com/watch?v=cQeOp7a8QMI