Books permit us to voyage through time, to tap the wisdom of our ancestors. The library connects us with the insights and knowledge, painfully extrac… - Carl Sagan

Seances occur only in darkened rooms, where the ghostly visitors can be seen dimly at best. If we turn up the lights a little, so we have a chance to see what’s going on, the spirits vanish. They’re shy, we’re told, and some of us believe it. In twentieth-century parapsychology laboratories, there is the ‘observer effect’: those described as gifted psychics find that their powers diminish markedly whenever sceptics arrive, and disappear altogether in the presence of a conjuror as skilled as James Randi. What they need is darkness and gullibility.

I do not imagine that many people in the fifteenth century ever wondered if they were living in the Italian Renaissance.

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, subsuming Caretakers and Tunnel builders, there is an intelligence that antedates the universe.