Quotes from book
Three Roads to Quantum Gravity

Three Roads to Quantum Gravity: A New Understanding of Space, Time and the Universe is a non-fiction book by American theoretical physicist Lee Smolin. The book was initially published on May 30, 2001 by Basic Books as a part of the Science Masters series.
“Time is described only in terms of change in the network of relationships that describes space.”
Three Roads to Quantum Gravity (2000)
“It is absurd in general relativity to speak of a universe in which nothing happens.”
Three Roads to Quantum Gravity (2000)
“There is no fixed, eternal frame to the universe to define what may or may not exist.”
Three Roads to Quantum Gravity (2000)