Sagan intended this as an allusion to Thomas Carlyle. 'A sad spectacle!' exclaimed Thomas Carlyle, contemplating the possibility that millions of planets circle other suns. 'If they be inhabited, what a scope for pain and folly; and if they be not inhabited, what a waste of space!' Contact is not the only place this allusion occurs in Sagan, who previously quoted Carlyle during a conference on extraterrestrials; Google makes a video of the conference available online.
Heh... I wonder how many people don't even know that Contact was originally a book by Carl Sagan. Although the movie was more true to the book than most, the book was much better than the movie, as is usually the case.
"The universe was made on purpose, the circle said. In whatever galaxy you happen to find yourself, you take the circumference of a circle, divide it by its diameter, measure closely enough, and uncover a miracle--another circle, drawn kilometers downstream of the decimal point. There would be richer messages farther in. It doesn't matter what you look like, or what you're made of, or where you come from. As long as you live in this universe, and have a modest talent for mathematics, sooner or later you'll find it. It's already here. It's inside everything. You don't have to leave your planet to find it. In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist's signature. Standing over humans, gods, and demons, there is an intelligence that antedates the universe.
The circle had closed. She found what she had been searching for.
"Young Ellie: Dad, do you think there's people on other planets?
Ted Arroway: I don't know, Sparks. But I guess I'd say if it is just us... seems like an awful waste of space."