“You, who know better than any one the motley world of cosmopolites, understand why I have confined myself to painting here only a fragment of it. That world, indeed, does not exist, it can have neither defined customs nor a general character. It is composed of exceptions and of singularities.”
— Paul Bourget, Cosmopolis (1892) Introduction
“It may be that our role on this planet is not to worship God but to create him.”
— Arthur C. Clarke Clarkfoundation.org
“Singularity is almost invariably a clue. The more featureless and commonplace a crime is, the more difficult it is to bring it home.”
— Sir Arthur Conan Doyle as Sherlock Holmes, The Boscombe Valley Mystery The Adventures of Sherlock Holmes, Strand Magazine (1891)
“Each word is a singularity, or is connected with a singularity, in our way of understanding existence.”
— Léon Rosenfeld (1904–74) As quoted in A Question of Physics: Conversations in Physics and Biology (1979), Paul Buckley and F. David Peat, Routledge and Kegan Paul, London, p. 29.
“The "hard" science-fiction writers are the ones who try to write specific stories about all that technology may do for us. More and more, these writers felt an opaque wall across the future. Once, they could put such fantasies millions of years in the future. Now they saw that their most diligent extrapolations resulted in the unknowable … soon.”
— Vernor Vinge, "The Coming Technological Singularity" (1993)
“The true human being … is the meaning of the universe. He is a dancing star. He is the exploding singularity pregnant with infinite possibilities.”
— David Zindell, The Broken God (1992)

Quotes via Wikiquote (CC BY-SA), each with its original source.