The subtitle of this book is “Science as a Candle in the Dark,” which captures the theme beautifully. The book seeks to teach the importance of the scientific method in determining truth from error. It’s careful not to assert that the scientific method is the only method, but is clearly the most effective, as given by its success. The value of critical and sceptical thinking is discussed, with many examples. One of the best chapters is the one where the author discusses what he calls the “baloney detection kit,” covering the various logical fallacies, such as ad hominem abuse, appeal to authority, causation mistaken for correlation, etc.
I confess I wasn’t prepared for how fun this book was going to be to read – and that’s chiefly down to the type of subject matter that Sagan handles, such as his lengthy comparison of the UFO abduction phenomenon to the old stories of religious visions. He also spends some time going into psychic phenomena, and even Satanic ritual abuse.
If there is one weakness in the book it’s that it doesn’t quite do justice to those occasional areas of human enquiry where the scientific method lets us down. I’m something of an occult dabbler, and I’ve made successful experiments in psychokinesis. I was curious to see if my convictions about my own work could stand up against Sagan’s assertions. He is a little overly dismissive of psychic phenomena, and while discussing this subject he seems to forget for a moment that the scientific method is just a method, not our only means of determining truth. The reason the scientific method has thus far failed to give us proof of psychic phenomena is because the phenomena are extremely slippery and hard to replicate. A genuine experience of ESP might be a sudden feeling of dread that something terrible has happened to a friend, then later finding out that he’s been in a car wreck. Such an experience cannot be replicated in a lab, because the experiencer has no idea what he did to prompt it.
The arena of religion understandably comes under fire for anti-scientific dogmatism, but Sagan handles the topic respectfully, while not pulling his punches.
Overall, this is an excellent book. The first step in truth-seeking is not to determine what to believe, but to learn how to think. The Demon-Haunted World provides an excellent guide to that initial enterprise. Sagan is masterful at making science understandable for the lay reader.