Time and Time Again : EINSTEIN’S DREAMS, By Alan Lightman (Pantheon: $17; 179 pp.)

It is 6 a.m. at the Swiss Patent Office in Bern in the year 1906. A gray light begins to reveal the contents of the room: the desks, which appear “soft and shadowy like large sleepy animals”; the shelves containing patent applications for a better drill, a quieter typewriter and a host of other things. “It is a room full of practical ideas.”

Except for those of the employee dozing at one of the desks. His trousers are too big, and his head is shaggy and contains no practical ideas at all. It is used for dreams and calculations based upon the dreams; it belongs to Albert Einstein, who has fallen asleep after completing his paper on the nature of time.

Alan Lightman, a physicist who teaches at MIT and writes about what might be called the mind of science and the minds of scientists, has turned to a fictional form to suggest the strange intuitive light that flickers at the frontiers of discovery. What the Einsteins do is not resolve our mysteries but enlarge them.

“Einstein’s Dreams” is 30 brief fables that imagine the subconscious seed bed from which the thinker’s theory of time--part of his work on relativity--emerges. For example, Lightman’s Einstein has been an insomniac dreamer. Each dream has evoked an alternative world in which time moves in a different way. On that gray Bern morning, in those crumpled sheets of paper, he has chosen the one he will build his work upon.

Lightman invents the others: worlds where time runs backward, stops suddenly dead, starts up suddenly, or moves in eddies, in jerks, or in three different dimensions at once. There is time that goes terribly slowly, time that goes at different speeds in different towns, time that is sticky and time that runs a perpetual loop.

The author plants each of these notions in vignettes about hypothetical realms like those of Gulliver or perhaps of Italo Calvino. His tiny Lilliputs and Laputas, no longer than 500 or 600 words each, are entrancing. They are set in 30 alternative Berns or sometimes in an alternative Zurich or Fribourg. Alternative Swiss move through them in patterns governed by 30 alternative versions of time. They are miniature people, improbable people, fragile people with the intensified humanity and comical poignancy of a puppet theater that time works as it tries out its alternative stories.

In one, time’s flow has eddies that circle backward. Those who are carried back into the present wear dark suits, talk softly and have to be very careful. One woman cowers in the bushes so as not to be seen or to kick up dust. Dust would get on a passerby’s shoes, he would stop to clean them, he would forget an errand for his wife, she would grow pettish and cancel a lake excursion, thereby failing to make the acquaintance of the young woman who was to become their son’s wife and the grandmother of a man crucial to the signing of a European treaty in 1979. So the time-drifters have to make a point of doing nothing to interfere with the present as they wait to be eddied back where they belong.

In another world, time moves more slowly the farther you get from the planet’s center. In order to delay aging, people build their houses on the tops of mountains; the more privileged mount theirs on stilts half a mile above the peaks. They despise their lower-down neighbors, and they especially despise the improvident who insist on enjoying the meadows and valleys. But at such rarefied heights, they grow thin and dry, and age faster, in fact.

Lightman’s lovely irony is at work. His time variations are never merely conundrums. In a world where time moves in three dimensions, a man stands on his balcony and gazes at a red hat lying in the snow. He thinks of visiting a fascinating but difficult woman in Fribourg. In the first dimension, he stays home, meets a nicer woman and lives in peaceful happiness. In the second, he goes, stays with the enchanter and lives in passionate happiness. In the third, he goes, stays an hour, returns inconclusively and stands on the balcony gazing at the red hat. That he does all three things is the conundrum; the emotion of this oddly moving story is in the red hat.

In another world, the inhabitants are divided into two groups. The first lives by schedules and clocks, by a mechanical time that never varies. The second lives by the rhythms of their bodies and their emotions. Intergroup encounters can be perilous, but Lightman pulls back from the notion’s agreeable dryness to something more haunting. A bargeman moves his craft along the river, measuring off fathoms and minutes. Through the evening mist, a pair of lovers awake to the lights going by in the dark, and are surprised to see it is night.

At one level, “Einstein’s Dreams” is a provocative exploration of time’s illusive nature and polymorphous possibilities. It sketches aspects of relativity with a light allusiveness that makes its astonishment, if not its entire meaning, as clear to the non-scientific reader as words alone can manage.

But Lightman does far more than that. He is an artist who paints with the notion of time; he makes a delicate link between its philosophical and its existential meanings. Time weeps and laughs in the perplexed inhabitants of his fables, and it glitters in the radiant mountaintops and painted sky that suddenly overshadow their humanity in a story about time ending. What ends, of course, is time as the marker of what passes. What remains, with the mountains, is time as what lasts.

The author has a winning sense of place, of the look and smell and feel of things. Time, however variously it moves, frets and chivvies his towns and townspeople. The solace they get from a plate of smoked beef, or a glass of beer or an embrace, is palpable. Whatever time may do in any of the alternative worlds, Lightman is on the side of the universally present moment.

Here and there, in interludes, he gives us homely glimpses of Einstein and his friend Besso. At one point, Einstein tells Besso that he wants to understand time in order to get to “the Old One.” Besso points out that the Old One may not be interested, and, besides, knowledge is not the same as closeness. In another interlude, they go fishing, and when Einstein laughs and jiggles the boat, “the clouds rock with his laughter.” The universe varies with its observer.

Lightman has done much more than make relativity visible by seeding it with human stories. He makes his human stories more deeply visible by seeding them with relativity. The delightful and disconcerting surprise when we finish reading about his 30 alternative worlds of time is to realize how many of them--slowness, expansion, contraction, speed, standstill, jerkiness, even reversibility--trouble and distract the spirit in our very present non-alternative one.