But what happened to Einstein after he retired is the same thing that happens to anyone who loses his sense of purpose. Einstein became depressed and listless. He stopped taking his dog for walks. He lost his energy. He was no longer looking forward to getting up in the morning.
A sense of purpose has a huge impact on your everyday mood.
After he'd had enough of this, Einstein decided he might still have something to contribute to the world. He decided to do two things:
1. develop a plan to control the destructive use of atomic power
2. to discover peacetime uses for atomic power
He came alive! The luster was back. He took his dog for walks again. Why? Because he had a sense of purpose.
And as a result of his decisions and his efforts to make those goals a reality, medical and electrical uses for atomic power were found. He gave speeches and helped stir up interest in a worldwide police force that eventually culminated in the founding of the United Nations.
Mind you, this was all accomplished after the age of seventy, after he had decided he had nothing else to accomplish. "Nothing contributes so much to tranquilizing the mind," wrote Mary Wollstonecraft Shelly, "as a steady purpose — a point on which the soul may fix its intellectual eye."
It is physically and psychologically healthy for a human being to have a strong sense of purpose. The state of mind you have when you're absorbed in the accomplishment of a purpose is called "flow," which is an engaged, pleasant state of focus.
Those who have learned to develop a sense of purpose and who have learned to become engrossed in the achievement of purposes are the most likely to be happy and healthy. This has been shown in scientific studies and you've seen it in your everyday observations.
Happy people are purposeful people because the most reliable self-created source of happiness is taking action along a strongly-held purpose.
Flow has been the subject of quite a bit of research. For example, swimmers who experienced flow while training made the most progress by the end of the training. In other words, experiencing frequent flow allowed them to develop their abilities faster.
Another study accentuated those findings. It found that of all the things that influence how successful someone becomes in their sport or skill — in whatever field — the most influential factor was how much flow they experienced while doing it. In other words, the amount of absorption they had was the best predictor of who would develop their talent the most.
A sense of purpose brings out the best in people. In his book, Carrying the Fire: An Astronaut's Journeys, Michael Collins wrote about the enthusiasm of the people in the Apollo space program in 1964. "…the goal was clearly and starkly defined," wrote Collins. "Had not President Kennedy said before the end of the decade?"
They had a clear goal that the people at NASA were excited about. The moon! The impossible goal! The goal they said could never be done! People showed up early, worked hard, and stayed late.
As Collins put it, "People knew that each day was one day closer to putting man on the moon…"
This is the electrifying power of a strong sense of purpose. You want to get into a good mood? Get a strong sense of purpose.
Mihaly Csikszentmihalyi, one of the principle researchers into flow, says we usually see work as a necessary evil, and we feel leisure is what we want: time on our hands. Free time. Time with nothing to do. We long for it. And yet, he says, "free time is more difficult to enjoy than work."
Or as Jerome K. Jerome put it, "It is impossible to enjoy idling unless there is plenty of work to do."
Work provides clear goals more often than leisure and a clear goal is the first and most important requirement of flow.
If you want to experience flow, you must have a purpose. Work provides a purpose. It provides something to become absorbed in, so it provides opportunities for flow.
To get flow from leisure, you have to provide the purpose. Many people don't know that, which means many people don't get much enjoyment from their coveted leisure; it isn't satisfying like they wish it would be. Some even suffer during leisure.
Sandor Ferenczi, a psychoanalyst in the early 1900's discovered that anxiety and depression occurred more often on Sundays than any other day of the week. Since that time, many observers have noticed that vacations and retirement also tend to produce anxiety and depression, just as they apparently did for Einstein.
When we're not on the job — when we're not given a clear purpose — many of us are feel adrift and don't know what's missing. Clearly, a large percentage of people don't have a strong sense of purpose for their off hours, and it's a shame. Purpose is king.
A purpose to sink your teeth into gives your mind a healthy, productive focus and prevents it from drifting into negativity. Without goals, wrote Csikszentmihalyi, "the mind begins to wander, and more often than not it will focus on unresolvable problems that cause anxiety."
But you can avoid that and send your mood into a new stratosphere with a clear goal and a strong sense of purpose.
Adam Khan is the author of Self-Help Stuff That Works and Cultivating Fire: How to Keep Your Motivation White Hot. Follow his podcast, The Adam Bomb.