Carl Sagan - The Demon-Haunted World: Science As a Candle in the Dark

My favorite genre of science books are those that discuss the relations between science, wonder, and credulity. Michael Shermer wrote an intelligent general discussion of these issues ("Why People Believe Weird Things"), Richard Dawkins elaborated on the usefulness of scientific thought ("Unweaving the Rainbow"), but Carl Sagan beat them all with "The Demon-Haunted World".

Sagan's demons are metaphorical - but he sees them as being just as harmful as those which cast the people of the Dark Ages into fear. The demons that Sagan discusses are ignorance. Apathy. Ideology overcoming truth. Paranoia. According to Sagan, these are the demon's that thrive on modern man's fear of the unknown, and which can only be overcome by critical thinking and the love for new knowledge that only science can bring.

What I love so much about this book is its sense of wonder. Using lots of interesting anecdotes and personal accounts, Sagan outlines the principles that can lead to a better-informed society - but at the same time, he makes the reader want to go out and start conducting experiments. Science is not something to fear, but something to embrace.

"The Demon-Haunted World" is organized as a series of interrelated chapters, sometimes covering the same ground, but usually counterpointing each other remarkably well. The book doesn't have quite the flow of a clear, developing argument - but this is one of its virtues, as Sagan shifts from one topic to another in his discussing of the myriad applications of scientific thought to our lives.

Sagan came to fame with his television special "Cosmos", and this book deals with a different (but equally compelling) area of science: epistemology. It's shocking to me how people accept some of science's benefits, while rejecting its other conclusions; Sagan apparently saw this as a major problem too. While this book is wide-ranging in its subject matter, Sagan occasionally discusses the way pseudo-scientists, while often denying the efficacy of science, try to adapt its credibility to their own ends.

His writing style is plainspoken, which might be a breath of fresh air for readers who come to this book, as I did, after having read the somewhat more complex technical works of Richard Dawkins. Though in this book there's much discussion of scientific topics in relation to the methods of critical thinking, there's also more abstract philosophical musings that target the crises of credulity that Sagan observed.

The very title invokes the perennial conflict between religion and science - but thankfully, Sagan doesn't press this point. Though he was apparently an agnostic, he clearly respected the religious beliefs of others, as long as they didn't infringe on our rights. And so, he criticizes witch burnings, creationism, and the "Satanic panic" of the '80s without mocking the religious beliefs taken too far that led and still lead to such excesses.

In a number of reviews of "The Demon-Haunted World", I've seen people saying that Sagan thinks too much in terms of black-and-white - for instance, saying that Sagan never addresses the beliefs of moderate religionists, only focusing on fundamentalism. While it's accurate to say that, Sagan clearly doesn't see moderate religion as the problem, but only anti-intellectual fundamentalism - it's that simple.

"The Demon-Haunted World" begins with a discussion of science as "the most precious thing". When I first read this book a couple years ago, having been bored to death by all my science classes in school, this chapter was a revelation. Here, Sagan eloquently discusses the scientific method, focusing on the rigor that forces science to reject unsupported hypotheses and bad data, regardless of one's emotional investment in them.

From here, Sagan begins to target "alien abductions" and topics of this sort. Arguing that the widespread belief in aliens is chiefly based on poor scientific thinking, Sagan is clearly at his most controversial here. He talks at length about the relations between the credulous media and the consistent myth of alien abductions as an accepted fact.

Soon, Sagan moves into a more general discussion of credulity. In "The Dragon In My Garage", he outlines the philosophical issue of the burden of proof. In perhaps the most useful chapter, "The Fine Art of Baloney Detection", he lists the multiple errors of thought, such as special pleading, ad hominem, and argument from authority, that lead to overcredulity. This chapter is an invaluable resource for anybody interested in combatting bad arguments, and I think it ought to be required reading in schools.

In the next few chapters, Sagan discusses the phenomenon of "anti-science", otherwise-intelligent people rejecting the truths of science to maintain their mystical outlooks. Concluding with some politically-oriented chapters on the crises of American education, Sagan again flirts with controversy, but offers some fascinating food for thought.


"The Demon-Haunted World" will annoy anybody not willing to suspend their own prejudices. Though I think Sagan had a political agenda to some extent in writing this book - which makes itself clear, most of all, in the concluding chapters - his broader aim is to equip the "common man" with the tools to distinguish between fact and fantasy. There he succeeds admirably; this is another brilliant book from Sagan that popularizes scientific principles without oversimplifying them.