My life has been better because of a key decision I made many years ago. I’m not sure exactly when it happened or if it even occurred in a single moment, but somewhere along the way I decided to be a good skeptic and think like a scientist every day. This simple but crucial choice has saved me time, money, and probably a lot of embarrassment and regret, too. Who knows? It might have saved my life. I didn’t take this path because I wanted to feel superior or look down on others for believing things that probably aren’t true. Skepticism is not arrogance. I didn’t make the decision because I wanted a cold and unemotional life devoid of mystery. Skepticism does not drain the joy from life; in fact, it can add much to it. Thinking like a scientist doesn’t mean one can’t enjoy fiction and fantasy and dream impossible dreams. Thinking skeptically certainly does not require one to deny or ignore the many unanswered questions all around us. I simply thought that it made sense to embrace skepticism because I wanted to minimize the amount of my life I wasted on lies, mistakes, and misperceptions. I also didn’t want to run the risk of being a sucker or easy prey for con artists.

If I hadn’t been skeptical about every unusual and important claim that came along over the years, how many crackpot medical treatments might I have squandered my money on? Would one or some of them have harmed my health? It’s impossible to know, but I’m glad I didn’t risk it. How many smooth-talking crooks and seductive but worthless products failed to fool me? How many organizations based on lies or hopelessly dubious claims did I not join, thereby not wasting precious hours, days, and years of my life? How much stronger and more confident have I been when facing each new day because virtually all my fears and anxieties stop where known reality ends?

I worry about those who are weak skeptics. I feel sad when I see people stumble. There shouldn’t be so many victims. I believe anyone can think like a scientist and everyone should want to. This book will show you how. If you are already a good skeptic, it can help make you a better one. It will also show you more effective ways in which you might spread the word among friends and family members who may be a little too loose with their beliefs. Thinking like a scientist doesn’t guarantee anyone a perfect life that is without mistakes and free from danger, of course. But it does put you in the best possible position to successfully navigate your way through this crazy world of ours. Insufficient skepticism is perhaps the most unrecognized and underreported global crisis of all. Applied vigorously and consistently, skepticism could change humankind for the better overnight. It is our most neglected defense and underutilized weapon. Politicians never mention it. Teachers rarely teach it. Few parents encourage it. So, with little resistance, the world keeps spinning its lies and delusions, generation after generation. The cost of leaving so many unproven claims and bogus beliefs unchallenged can be seen in diminished and lost lives. Most people underestimate how easy it is for healthy and bright people, including themselves, to be seduced by the irrational ideas of others or led to fantasyland by the natural processes of their own brains. One of the goals of this book is to make sure you don’t make that mistake.

This may be described as an instructional or educational book, I suppose, but it is very important for readers to recognize that it is not a collection of facts or a presentation of arguments meant to instruct people on what to think. This book is about how to think. I’m not looking for loyal teammates or hoping to enlarge the choir that I preach to. I want to inspire readers to think for themselves in sensible ways that allow them to chart their own course in life without being tripped up by one irrational belief after another. I absolutely do not want readers to look to me as some voice of authority that they can rely on as a shortcut to their own thinking. For example, I don’t think psychics and mediums can read minds and carry on two-way conversations with dead people. But don’t take my word for it. Figure it out for yourself like a good skeptic would. I’ve been wrong before; maybe I’m wrong about this.

This book is a call for self-reliance. It’s about you. In order to live in the real world and hopefully avoid becoming the pathetic plaything of crooks, kooks, and sincere-but-deluded people, you have to use and rely on your brain, no one else’s. Sure, expert opinion and information from credible sources matter, but not nearly as much as your own ability to react wisely when an extraordinary claim knocks on your door. For your own sake, you need to know what to do so that you can determine whether or not you should let it in or slam the door shut.

Have no doubt, there are an infinite number of weird claims, unusual ideas, dangerous ideas, and unlikely-to-be-true beliefs stalking you every day. People make up new claims every day, so we can’t possibly carry around in our heads tailored, preloaded responses for each one. A good skeptic is ready for all of them simply by knowing how to think critically and by understanding the wisdom in questioning everything. A good skeptic also needs to know basic facts about what the human brain needs in order to work well, because it all starts there. Researchers continue to accumulate evidence that show nutrition and physical activity are more important than we ever knew. When spreading the word about science and skepticism to others, it also helps to know a minimal amount of background information and alternate explanations for some of the more popular beliefs. This book will help with all that, too.

Skepticism is an important issue for everyone. It’s something we all need, regardless of intelligence, education, location, social status, or income. The mere fact that you have a human brain makes you extremely vulnerable to believing things that are not true. There is no escaping this. The natural processes and instincts we all have set us up to fall for things that are not true or real. It comes with being human. If you deny this and think you are immune, it only makes you more vulnerable to nonsense and delusion.

Fortunately, the same brain that so often fails us and tricks us can also be very good at protecting us. It can be the most vigilant and effective guardian you could ever have. Or it can be a source of constant problems. It’s up to you.

—Guy P. Harrison

Earth