The Demon-Haunted World

The Demon-Haunted World: Science as a Candle in the Dark is a 1995 book by astrophysicist Carl Sagan.

In the book, Sagan aims to explain the scientific method to laypeople, and to encourage people to learn critical and skeptical thinking. He explains methods to help distinguish between ideas that are considered valid science and those that can be considered pseudoscience. Sagan states that when new ideas are offered for consideration, they should be tested by means of skeptical thinking and should stand up to rigorous questioning.

Themes

Science to Sagan is not just a body of knowledge but a way of thinking. The scientific way of thinking is both imaginative and disciplined, bringing humans to an understanding of how the universe is, rather than how they wish to perceive it. Science works much better than any other system because it has a "built-in error-correcting machine". Superstition and pseudoscience get in the way of many laypersons' ability to appreciate the beauty and benefits of science. Skeptical thinking allows people to construct, understand, reason, and recognize valid and invalid arguments. Wherever possible, there must be independent validation of the concepts whose truth should be proved. He states that reason and logic would succeed once the truth were known. Conclusions emerge from premises, and the acceptability of the premises should not be discounted or accepted because of bias.