Pic by Jacqueline Castel, graphic by Josh Romero

The 30-Day Mental Challenge

All you need to do is try

Mitch Horowitz
2 min readNov 8, 2020


American philosopher William James (1842–1910) yearned to find a practical spirituality, one that produced concrete improvements in happiness.

The Harvard physician grew encouraged, especially in his final years, by his personal experiments with New Thought, which he called “the religion of healthy-mindedness.” I challenge today’s seekers to continue James’s search for a testable, workable spiritual system. Will join me in a thirty-day experiment that puts positive-mind metaphysics to the test?

It is based on a passage from a 1931 book, Body, Mind, and Spirit by Elwood Worcester and Samuel McComb, in which a prominent scientist described radically improving his life through a one-month thought experiment. I have condensed his testimony:

Up to my fiftieth year I was unhappy, ineffective, and obscure. I had read some New Thought literature and some statements of William James on directing one’s attention to what is good and useful and ignoring the rest. Such ideas seemed like bunk — but feeling that life was intolerable I determined to subject them to a month-long test.

During this time I resolved to impose definite restrictions on my thoughts. In thinking of the past, I would dwell only on its pleasing incidents. In thinking of the present, I would direct attention to its desirable elements. In thinking of the future, I would regard every worthy and possible ambition as within reach.

I threw myself into this experiment. I was soon surprised to feel happy and contented. But the outward changes astonished me more. I deeply craved the recognition of certain eminent men. The foremost of these wrote me, out of the blue, inviting me to become his assistant. All my books were published. My colleagues grew helpful and cooperative.

It seems that I stumbled upon a path of life, and set forces working for me which were previously working against me.

I stumbled upon a path of life…

Let’s repeat this experiment together: 1) Choose your start date, 2) write out the full quoted passage above by hand (never underestimate the value of that), and 3) add: “I dedicate myself on this day of ___________ to focus on all that is nourishing, advancing, and promising for thirty days (signed) ___________________________”

That’s it.

If you wish, email me your results via my website (I neither harvest nor keep emails). I will report the outcome in a future piece

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I discuss the 30-Day Mental Challenge with Duncan Trussell here.



Mitch Horowitz

"Treats esoteric ideas & movements with an even-handed intellectual studiousness"-Washington Post | PEN Award-winning historian | Censored in China