Book Review - "The Demon-Haunted World" by Carl Sagan

Astronomer Carl Sagan’s 1996 book, The Demon-Haunted World is the ultimate guide to critical thinking. Carl Sagan asks, “How can we make intelligent decisions about our increasingly technology-driven lives if we don’t understand the difference between the myths of pseudoscience, New Age thinking, and fundamentalist zealotry…and the testable hypotheses of science?”

Sagan offers a lengthy explanation of how the scientific method works, and how it is demonstrably more successful than any of its pseudoscientific imitators. He teaches the importance of having a skeptical worldview, especially of extraordinary claims. As he stated in Cosmos, “Extraordinary claims require extraordinary evidence.” Sagan explains the necessity of Ockham’s Razor – the rule of thumb that people should not assume anything that the evidence does not require them to assume – in critical thought. He systematically exposes the absurdity behind many of the most popular modern-day forms of pseudoscience, including astrology, homeopathy, psychics, alien abductions, Freudian psychoanalysis, doomsday predictions, graphology, and numerology.

While some have criticized the book as being anti-religious, Sagan himself disputed this characterization. He was clearly an agnostic, but had a deep appreciation for the sense of wonder that religion could inspire and recognized that it had much in common with his own appreciation for science. He does take certain religious views to task – such as the ideas of young-earth creationism, faith healing, and divine intervention. However, he notes that although “religions are often the state-protected nurseries of pseudoscience…there is no reason why religions have to play that role.” Sagan was a strong advocate of finding common ground between the religious and scientific communities: a central theme of his novel Contact.

14 years after its original publication, The Demon-Haunted World seems more topical than ever. The applications of critical thinking extend far beyond the realm of science. By being skeptical of unusual claims, we can better gauge the veracity of some of the odd statements we routinely hear from any authority, including our politicians, educators, corporate gurus, and religious leaders. In my opinion, there is no more important skill that our schools should teach students than the process of thinking critically. Unfortunately, most high schools and many universities don’t offer any classes in critical thought, even as electives. Carl Sagan’s The Demon-Haunted World can guide us where our schools do not.

The Demon-Haunted World was Sagan's last book before his death in 1996. Although it never reached the same level of popularity as some of his other works such as Cosmos and Contact, I think it is his most important work for the layperson. The Demon-Haunted World has shaped my view of the world more than any other book.

5/5 stars

Resolving Fermi's Paradox

If intelligent life exists elsewhere in the universe, where is everyone? Enrico Fermi’s 1950 question has elicited many theories in the sixty years since. If advanced life was as commonplace as Frank Drake or Carl Sagan believed, it seems unlikely that not a single extraterrestrial civilization would have made itself known to us.

Some, like futurist Ray Kurzweil, believe that this means that we are alone in the universe: the product of a series of astronomically unlikely occurrences. Kurzweil reasons that any advanced civilization would use all the matter of its own planet for computing, then radiate outward from their home world. The fact that no one seems to have done this already is supposedly evidence that we are alone.

I think this is a remarkably anthropocentric view of the universe. Both Fermi’s Paradox and Kurzweil’s reasoning employ the same faulty assumption that extraterrestrial life would act the same way that humans might. How can we possibly guess the goals of an extraterrestrial civilization when we don’t even know how our own civilization will act in the future? Why should we assume that extraterrestrials will be expansionists, desiring to conquer (or even communicate with) the rest of the universe? This is a remarkably human trait to project onto other potential civilizations. It’s entirely possible that extraterrestrial life does exist, but is simply not interested in interacting with us, content with not venturing far from their home worlds. Any civilization capable of interstellar travel or communication will almost certainly have access to anything it wants at home, and perhaps would have no particular reason to be interested in a pale blue dot populated by bipedal apes.

There is another, darker explanation for the lack of contact with extraterrestrials. If advanced civilizations tend to eliminate any inferior civilizations with which they come in contact, then we will have no evidence of them until immediately before our extinction, if at all. The fact that we have not yet been eliminated, then, simply means that no other advanced civilizations are aware of our presence yet. We can employ the Anthropic Principle here: We would not be here to speculate about Fermi’s Paradox if we had been discovered by another civilization.

These are the explanations for Fermi’s Paradox which seem the most plausible to me. The least plausible explanation is the one Kurzweil suggests: That we are alone. Even if advanced life developed in only one in a billion solar systems, there would be trillions of civilizations in the vastness of our universe. Finding them, however, may be much more difficult. Perhaps a truly intelligent civilization would leave no evidence of its existence at all.