What is the author's tone in Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan?

The tone of Pale Blue Dot reflects Carl Sagan's key values. He is an ardent and well-known secular humanist, believing that humanity has great value but that there is no God or gods for us to ask for help. Instead, we are alone. Sagan's secular humanism comes out explicitly in the early chapters, particularly in Chapter 4, where Sagan argues that there is no evidence that the universe is designed for humanity.