It is better to light one candle than to curse the darkness. – Chinese proverb
Sagan calmly explains in the book that there are natural physical phenomena that are provable, and others that are not, and that there exists in the scientific method a mechanism for telling this stuff apart.
Carl Sagan was a champion of science. He made physics and astronomy accessible to everyone, and did it in a way that inspired hope and wonder. He was also a well-known skeptic, but he was not known as a debunker. In the The Demon-Haunted World, however, he pulls no punches while challenging superstitious beliefs.
The book is prefaced with an adage “It is better to light one candle than curse the darkness”. Sagan shows us how we can illuminate our own world by giving us 25 essays on science, reason, and critical thinking. Each of the essay chapters can be digested independently, but they are held together by a common idea that the scientific method is not just a tool for expanding the scientific body of knowledge, it’s a tool that every person can use every day to make the world a better place.
Chapter by chapter Sagan debunks pseudo-scientific beliefs including the Face on Mars, repressed memories, UFOs, ghosts, and faith healing. All the while he makes it clear that it is not stupidity that causes people to fall for these untruths, but our natural human instincts. As humans we want to feel comforted, we look for patterns everywhere, and we naturally respond to arguments from authority. Through each debunking he shows that it’s not just knowledge but the tools we use to examine this knowledge that illuminates the truth. He puts all these tools together in the often-cited chapter “The Fine Art of Baloney Detection”.
Besides debunking these myths, the book also focuses on the importance of critical thinking to the survival of human rights and freedoms. Science requires that we are free to ask questions, to change our minds, and to challenge currently held beliefs. But these things are also vital to a free and democratic society. We can look back on the Dark Ages to see what happens when the opposite becomes the norm. Sagan sums this up passionately in the final chapter:
Education on the value of free speech and the other freedoms reserved by the Bill of Rights, about what happens when you don’t have them, and about how to exercise and protect them, should be an essential prerequisite for being an American citizen — or indeed a citizen of any nation, the more so to the degree that such rights remain unprotected. If we can’t think for ourselves, if we’re unwilling to question authority, then we’re just putty in the hands of those in power. But if the citizens are educated and form their own opinions, then those in power work for us. In every country, we should be teaching our children the scientific method and the reasons for a Bill of Rights. With it comes a certain decency, humility and community spirit. In the demon-haunted world that we inhabit by virtue of being human, this may be all that stands between us and the enveloping darkness.
The book is a great introduction to many skeptical topics. If you are new to skepticism, or looking for a book to give to someone that is, I highly recommend it. The essay format makes it easy to use as a reference if you just want to reread something on a specific topic. Subjects like the scientific method, confirmation bias, and logical fallacies are covered in many skeptical books. If you are a seasoned skeptic, you may find these parts of the book elementary. However, Sagan’s passionate writing style and personal anecdotes make for engrossing reading.