More Options

Thinking: An Unnatural Act

Book Review

Harriet Hall

Volume 36.3, May/June 2012

book cover

Unnatural Acts: Critical Thinking, Skepticism, and Science Exposed!
By Robert Todd Carroll. James Randi Educational Foundation, 2011. Available through and other electronic outlets exclusively in e-book format, $9.99.

Robert Todd Carroll, the author of the invaluable Skeptic’s Dictionary, has written an e-book that makes a perfect complement to his Dictionary. Titled Unnatural Acts: Critical Thinking, Skepticism, and Science Exposed!, it is essentially a primer on how to think.

The “unnatural acts” of the title are the acts of critical thinking, which don’t come naturally to our imperfect human brains. Our brains evolved an instinctive, intuitive, quick-and-dirty way of thinking that served our forebears well in their environment. A slower, more systematic, more critical way of thinking developed later and brought us science. It serves us better in today’s world but is more difficult to achieve. It requires education and concentrated effort to overcome the natural tendencies imposed on us by our evolutionary history.

The brain is an illusionist. It works by taking shortcuts, deceiving us into seeing things that aren’t there and believing things that aren’t true. We see the sun apparently moving across the sky, and it takes sophisticated understanding to overcome our first assumptions. Nature has programmed us to in­crease our chances of survival and reproduction, not to seek the truth. Religious literalists, New Age philosophers, and other true believers prefer magical thinking to science because we are hardwired to think that way. So creationism is often preferred over evolution, and fanciful medical quackeries are often preferred over effective treatments proven by scientific studies.

Critical thinking is hard. We must learn that we can’t trust our perceptions, memories, and intuitions. This requires education and practice. It’s frustrating to accept that our most cherished beliefs might be wrong. And it’s frustrating to know that success is elusive: the truths we learn will always be provisional, and we can never be certain whether we have looked at all the relevant data objectively.

In successive chapters, Carroll ex­plains:

In the final chapter, Carroll provides practical advice: fifty-nine ways to develop your unnatural talents in critical thinking, skepticism, and science. This list will be enhanced by the blog Unnatural Acts (, where he will be offering commentary and examples of the fifty-nine ways (plus a few more). Five appendices round out the banquet with detailed discussions of cell phone radiation, interstellar travel, acupuncture, what it really means to think critically, and step-by-step instructions on how to create your own pseudoscience. Refreshingly, he admits to errors of his own in The Skeptic’s Dictionary and corrects the record.

I laughed out loud at Carroll’s account of his first attempt at teaching logic as a newly minted philosophy PhD. “If I remember correctly, about twenty-five students signed up for the class and three finished. One of the three stayed because he liked me. Another stayed because he didn’t know how to drop a class. The remaining student understood the material in the text . . .” Over time, he progressed from teaching traditional logic to offering more useful courses in critical thinking as a way of life, emphasizing an understanding of the psychology of bias and other sources of error and embodying an attitude of intellectual humility, confidence in reason, intellectual curiosity, and intellectual independence.

Since critical thinking is important to every aspect of human life, he illustrates his points with examples drawn from every imaginable field: religions, UFO cults, psychology, alternative medicine, politics, parapsychology, martial arts, criminology, climate change, news media, vaccines, cell phone radiation, cancer clusters, and more.

Some of his examples will be familiar from other skeptical writings, like Clever Hans (the horse that responded to its owner’s unconscious body language) and the basketball/gorilla video illustrating inattentional blindness. Others were new to me, like the example of audio pareidolia where a Bob Dylan song lyric is heard as “throw my chicken out the window.”

There can never be too many books on critical thinking. Carroll’s is a worthy contribution to the skeptical literature: comprehensive, easy to read, and packed with entertaining examples that vividly illustrate the concepts. For those new to skepticism, it can serve as a valuable textbook for learning how to think. It will be useful to even the most jaded skeptics among us who think we already know how to think; we all still make mistakes, we need to be reminded anew of old lessons, and there is always more to learn.

Harriet Hall

Harriet Hall, MD, a retired Air Force physician and flight surgeon, writes and educates about pseudoscientific and so-called alternative medicine. She is a contributing editor and frequent contributor to the Skeptical Inquirer and contributes to the blog Science-Based Medicine. She is author of Women Aren’t Supposed to Fly: Memoirs of a Female Flight Surgeon and coauthor of the 2012 textbook Consumer Health: A Guide to Intelligent Decisions.