“What sense is there in continuing when one has seen the future?”

“Who would fare better in this world of fitful time? Those who have seen the future and live only one life? Or those who have not seen the future and wait to live life? Or those who deny the future and live two lives?”

“It is a world of impulse. It is a world of sincerity. It is a world in which every word spoken speaks just to that moment, every glance given has only one meaning, each touch has no past or no future, each kiss is a kiss of immediacy.”

“When a traveler from the future must talk, he does not talk but whimpers. He whispers tortured sounds. He is agonized. For if he makes the slightest alteration in anything, he may destroy the future. At the same time, he is forced to witness events without being part of them, without changing them. He envies the people who live in their own time, who can act at will, oblivious of the future, ignorant of the effects of their actions. But he cannot act. He is an inert gas, a ghost, a sheet without soul. He has lost his personhood. He is an exile of time.”

“Consider a world in which cause and effect are erratic. Sometimes the first precedes the second, sometimes the second the first.... Each act is an island in time, to be judged on its own. It is a world of impulse. It is a world of sincerity. It is a world in which every word spoken speaks just to that moment, every glance given has only one meaning, each touch has no past or future, each kiss becomes a kiss of immediacy.”

“In this world, time has three dimensions, like space. Just as an object may move in three perpendicular directions, corresponding to horizontal, vertical, and longitudinal, so an object may participate in three perpendicular futures. Each future moves in a different direction of time. Each future is real. At every point of decision, the world splits into three worlds, each with the same people, but different fates for those people. In time, there are an infinity of worlds.”

“Something else gets under your skin, keeps you working days and nights at the sacrifice of your sleeping and eating and attention to your family and friends, something beyond the love of puzzle solving. And that other force is the anticipation of understanding something about the world that no one has ever understood before you.Einstein wrote that when he first realized that gravity was equivalent to acceleration -- an idea that would underlie his new theory of gravity -- it was the "happiest thought of my life." On projects of far smaller weight, I have experienced that pleasure of discovering something new. It is an exquisite sensation, a feeling of power, a rush of the blood, a sense of living forever. To be the first vessel to hold this new thing.All of the scientists I've known have at least one more quality in common: they do what they do because they love it, and because they cannot imagine doing anything else. In a sense, this is the real reason a scientist does science. Because the scientist must. Such a compulsion is both blessing and burden. A blessing because the creative life, in any endeavor, is a gift filled with beauty and not given to everyone, a burden because the call is unrelenting and can drown out the rest of life.This mixed blessing and burden must be why the astrophysicist Chandrasekhar continued working until his mid-80's, why a visitor to Einstein's apartment in Bern found the young physicist rocking his infant with one hand while doing mathematical calculations with the other. This mixed blessing and burden must have been the "sweet hell" that Walt Whitman referred to when he realized at a young age that he was destined to be a poet. "Never more," he wrote, "shall I escape.”