How to Think Critically XI: The Null Hypothesis

So, you may have heard that Rhonda Byrne, author of The Secret, has a new book on the same subject, called The Power. Personally, I’m bewildered. Her first book promised to tell you how to get everything you’ve ever wanted. What possible room could there be for a sequel?

You might also have heard of the famous athletes who are wearing this bracelet, which, according to its makers, uses “processed titanium and holograms” which are “designed to interact with your body’s natural energy”, improving balance, energy, recovery time and flexibility. Although the makers admit they haven’t done any scientific studies, they allegedly have favorable testimonials by major athletes from Alex Rodriguez to Shaquille O’Neil – and hey, what more do you need than that?

I wonder if any believers in these products ever tried putting them to even a simple test. For instance, the authors of The Secret claim that reality is controlled by human willpower, and that you can use this effect to get yourself wealth and riches, a dream job, a trophy spouse, a house on the beach, a fleet of luxury sports cars, etc., etc. To judge if this is true, why not try it on a much simpler and more unambiguous outcome? Why not, for example, flip a coin and will it to come up heads twenty times in a row, or roll a pair of dice and command them with your mind to turn up seven every time? If the claims of The Secret are true, this should be easy to accomplish.

Or take these magical “hologram bracelets” – why wouldn’t you try, for example, shooting a hundred baskets (or hitting a hundred pitches, or a hundred putts, etc.) with and then without the bracelet, and see if the outcomes are noticeably different? Although it wouldn’t be a double-blind experiment, it would still be better than no testing at all.

What these stories show is that humans don’t have an instinctive grasp of the null hypothesis: the basic assumption, which you should always make in the absence of specific evidence to the contrary, that the events you see are due to chance. The Secret (and its inexplicable sequel) teach you to wish for what you want and keep on wishing until something good happens – and then triumphantly concludes that your wishes control the functioning of the universe. And if you don’t get what you want, the author leaves herself a convenient escape hatch: you did get what you wished for, you just unintentionally wished for something different than what you thought you wanted. The belief is structured so that nothing can convince its devotees of the existence of chance, no matter how tenuous the connections they must draw.

Failure to employ the null hypothesis causes belief in all kinds of pseudoscience and magic. There’s another example from a non-Western culture, this one from Pascal Boyer’s Religion Explained, a case study of the Zande people of Sudan by the British anthropologist E.E. Evans-Pritchard. When a house in the village collapsed, the people promptly concluded that those who lived there must have had enemies who were powerful witches. Evans-Pritchard pointed out, in vain, that the house was infested with termites. As the Zande explained, they were perfectly aware that termites could weaken the structure of a house and cause it to collapse. What they wanted to know why was it collapsed at that particular moment, when some people were sitting under it and not others – and that fact, they could think of no other way to explain than by blaming it on witches who bore those people ill will [p.13].

And then there’s this classic story, from James Randi’s Flim-Flam!: Gerard Croiset, a Dutch “psychic”,

attended a parapsychology seminar and competed with an East German “psychic”. During the encounter, the German concentrated on withering a flower, while Croiset concentrated on saving it. The flower survived, and Croiset crowed victory, saying that his powers were stronger. [p.143]

If you start with your conclusion and go looking for correlations that can be interpreted to support it, you’ll almost always find one if you look long and hard enough. The world is full of coincidences, and the human brain is extremely good at finding connections, regardless of whether they exist in reality or not. To avoid falling into this error, it’s essential to begin with the hypothesis of random chance and no connection, and then definitively rule it out with a repeatable experiment.

Other posts in this series:

Book Review: 1491
Movie Review: The Martian
Blood Moon Lunacy, or the Virtue of Vagueness
Weekend Coffee: CRISPR
About Adam Lee

Adam Lee is an atheist writer and speaker living in New York City. His new novel, Arc of Fire, is available in paperback and e-book. Read his full bio, or follow him on Twitter.