Alan Lightman (born November 28, 1948) holds a dual humanity and physics professorship at MIT. He is a bright, curious thinker and an engaging writer who circles uncertainty at the broadest and most intimate levels.

Lightman's In Praise of Wasting Time does more than extol the benefits of time-wasting, breaks, tempering pace, and play. With colorful research and personal examples, Lightman argues our natures have changed with technology.

I plead guilty myself. If I take the time to examine my own twenty-four hours per day, here's what I find: from the instant I open my eyes in the morning until I turn out the lights at night, I am at work on some project.

“Ye clouds! that far above me float and pause/Whose pathless march no mortal may control…” wrote Coleridge. Tiergarten Park, Berlin.

In Praise of Wasting Time, Lightman demonstrates how the mind forms different connections and ideas when untethered and unminded. Consequently, we need to activate breaks deliberately.

On one aspect of creativity, most researchers agree. It is something called "divergent thinking": the ability to explore many different avenues and solutions to a problem in a spontaneous and non-orderly fashion. 'Convergent thinking,' by contrast, is the more logical and orderly step-by-step approach to the problem.

Helpful is Lightman's exploration of what we gain in moments of play. He approached an authentic "renewal and consolidation of identity" by letting his mind wander.   On this site, I've approached these notions of self and self-discovery from a few different angles. Read more in The Importance of Walking About, Do Mirrors Tell Us Who We Are?, and Can Knowledge Be Gained Through Feelings?   
There is no greater question in my mind than how do we see more. Of ourselves, of the world, of each other. Whatever we might achieve in play, it does not take much to reap the rewards.

Divergent thinking does not cooperate on demand. It is not easily summoned. It does not follow the clock. It cannot be rushed. It withers and fades under external schedules and noise and assignments. Rather, it lollygags along on its own; it sprawls in the sun, taking its own time. Divergent thinking is associated with play, creativity, and curiosity.

Photograph by Ellen Vrana.

More than mere downtime, "wasting time" is necessary for creative ability and regeneration of our most profound consciousness. Annie Dillard called this the tiny space between the eyes and the monitor, the mind and the writing. When interrupted from this space, the locale of our lightness and depths, it can feel quite aggressive.

I contracted a phobia for which there is no name, the fear of being interrupted. (It may also be why, as I grew up, I came to prefer reading late at night, when the intrusive world has gone to bed.) Sometimes, at the peak of intoxicating pleasures, I am visited by panic: the phone or doorbell will ring, and someone will need me or demand I do something. Of course, I needn’t answer or oblige, but that is beside the point. The spell will have broken.
From Lynne Sharon Schwartz’s Ruined by Reading

The concept of wasting time and mindful wandering might be easier to grasp than the reality of it happening. "The world comes at me with its busyness," wrote Mary Oliver, a devotee of stepping outside the fray.

The Old Poets of China

Wherever I am, the world comes after me.
It offers me its busyness. It does not believe
that I do not want it. Now I understand
why the old poets of China went so far and high
into the mountains, then crept into the pale mist
From Mary Oliver's Why I Wake Early

A drift on a river, as recommended by Thoreau in A Week on the Concord and Merrimack Rivers, while Oliver Sack proposed a Sabbath to step apart.

Both echo Lightman's primary, concise conclusion:

Mental downtime is having the space and freedom to wander about the vast hallways of memory and contemplate who we are. Downtime is when we can ponder our past and imagine our future. Downtime is when we can repair ourselves.

Lightman writes equally beautifully about our existence in the vacuous unknowable and how to find meaning in an uncertain universe. He strides through different questions with each work, but all reflect a desire to enlighten. His work is a joy to read and a comfort to know.   Christopher Hitchens ended his 2011 book, Mortality with a line from Lightman’s 1992 novel Einstein’s Dreams. It essentially concluded that mortality was necessary for humans to come into their own, to exist apart from being someone’s son, grandson, or daughter.   
Hitchens died before the essay was finished, so whether he intended this to be the last line of his book is unclear. But it was certainly one of his last written thoughts.