""All our life," William James told us in the prologue, "so far as it has definite form, is but a mass of habits – practical, emotional, and intellectual – systematically organized for weal or woe, and bearing us irresistibly toward our destiny, whatever the latter may be."

James, who died in 1910, hailed from an accomplished family. His father was a wealthy and prominent theologian. His brother, Henry, was a brilliant, successful writer whose novels are still studied today. William, into his thirties, was the unaccomplished one in the family. He was sick as a child. He wanted to become a painter, and then enrolled in medical school, then left to join an expedition up the Amazon River. Then he quit that, as well. He chastised himself in his diary for not being good at anything. What's more, he wasn't certain if he could get better. In medical school, he had visited a hospital for the insane and had seen a man hurling himself against a wall. The patient, a doctor explained, suffered from hallucinations. James didn't say that he often felt like he shared more in common with the patients than his fellow physicians. 

"Today I about touched bottom, and perceive plainly that I must face the choice with open eyes." James wrote in his diary in 1870, when he was twenty-eight years old. "Shall I frankly throw the moral business overboard, as one unsuited to my innate aptitudes?"

Is suicide, in other words, a better choice?

Two months later, James made a decision. Before doing anything rash, he would conduct a yearlong experiment. He would spend twelve months believing that he had control over himself and his destiny, that he could become better, that he had the free will to change. There was no proof that was true. But he would free himself to believe, all evidence to the contrary, that change was possible. "I think that yesterday was a crisis in my life," he wrote in his diary. Regarding his ability to change, "I will assume for the present – until next year – that it is no illusion. My first act of free will shall be to believe in free will."

Over the next year, he practiced every day. In his diary, he wrote as if his control over himself and his choices was never in question. He got married. He started teaching at Harvard. He began spending time with Oliver Wendell Holmes, Jr. who would go on to become a Supreme Court justice, and Charles Sanders Pierce, a pioneer in the study of semiotics, in a discussion group they call the Metaphysical Club. Two years after writing his diary entry, James sent a letter to the philosopher Charles Renouvier, who had expounded at length on free will. "I must not lose this opportunity of telling you of the admiration and gratitude which have been excited in my by the reading of your Essais," James wrote. "Thanks to you I possess for the first time an intelligible and reasonable conception of freedom... I can say that through that philosophy I am beginning to experience a rebirth of the moral life; and I can assure you, sir, that this is no small thing."

Later, he would famously write that the will to believe is the most important ingredient in creating belief for change. And that one of the most important methods for creative that belief was habits. Habits, he noted, are what allow us to "do a thing with difficulty the first time, but soon do it more and more easily, and finally, with sufficient practice, do it semi-mechanically, or with hardly any consciousness at all." Once we choose who we want to be, people grow "to the way in which they have been exercised, just as a sheet of paper or a coat, once creased and folded, tends to fall forever afterward into the same identical folds."

If you believe you can change – if you make it a habit – the change becomes real. This is the real power of habit: the insight that your habits are what you choose them to be. Once that choice occurs – and becomes automatic – it's not only real, it starts to seem inevitable, the thing, as James wrote, that bears "us irresistibly toward our destiny, whatever the latter may be.""

 - Charles Duhigg