IF I WERE TALKING to children, alone and solemnly, I would tell them to consider one central choice in their lives as citizens. I would preach that, across the bloody years of modern history, there is only one choice that matters, on which all events must turn. They must choose their parentage.

Are we to be the children of Einstein, full of wonder and amazing ideas and a humble sense of human possibilities? Or have we become the arrogant children of Hitler, committed to a mechanistic certainty of our own righteousness?

Choose your parents. Children can't, of course, but I am reaching for an effective metaphor, a way of conveying my own sense of the historic choices of our extraordinary moment. I believe, at least, that the entire century has been a kind of epic struggle between those two intellects. The question is which will prevail.

Albert Einstein, the Jewish emigre from Nazi Germany, we remember mainly as a sweet grandfatherly face, an innocent expression concealing his wisdom, a physicist who discovered from his own childlike wonder the organizing questions for a new epoch. His questions revealed a confirmable paradox of life, one which guides modern science and invention in a way that most of us only dimly understand. The appearances of time and space, which guide our common sense and emotional reflexes and intellectual pretensions, mislead us in their certitude. All human perceptions are relative to time and place, centered in the self, and therefore never the whole truth.

Hilter, the fuehrer , whose madness was also a kind of genius, is better understood than Einstein certainly, remembered as a dreadful aberration of modern life. Yet Hitler also proposed organizing principles for the world and how it ought to work, a seductive legacy of clockwork industrialism and nationalistic superiority which is more enduring than we care to admit.

In my darker moods, I think the idea of Hitler will prevail, ultimately; that the mechanistic impulses of modern societies, including our own, will lead eventually to a terrible reckoning. But on most days I am an optimist, one who reads history as a progressive story of humankind changing its mind over time, revising its sense, that children can choose new parentage; we can claim a different inheritance.

Einstein once explained to another physicist: "It is the theory that decides what we can observe."

Without the new theory announced by Einstein, science could not have observed the revolutionary world of space and nuclear physics. In a similar vein, I am suggesting that Einstein's idea of relativity permits new vision in non-scientific realms, enabling us to observe ourselves and the world in truly modern ways. Unfortunately, politics and literature and religion, families and governments and individuals are still groping to understand the idea, much less to test it against reality.

The essence can be translated and applied to our commonplace experiences. I think of families and the strangely complicated realities bound up in them. Growing up, we all sat at the same dinner table, heard the same conversations, the arguments and triumphs. Yet each child left the family with a different memory of what happened there. Some remembered dark, heavy moments and others only sun and light. Children and parents recall totally different versions of the same event. If you doubt that, ask your children.

For Einstein, that was the key to comprehending the universe. When he was a teenage student, regarded as stubborn and inattentive, he is said to have asked himself a playful question:

"What would the world look like if I rode on a beam of light?"

Brushed with poetry, the question implied not merely that science observes a beam of light as it moves through time and space, but that the observer as well moves through time and space, complicating and changing every observation. In time, in the very few years it took Einstein to formalize the thought in scientific papers, the question toppled the universe of Isaac Newton, all the observable certitudes which had governed physics for 200 years.

In the early decades of this century, practical experiments confirmed the truth of Einstein's theory. The observable universe suddenly contained new paradoxes that refute our senses. There is no universal time, shared by all. Every experience, every observation, is shaped by its own observer, trapped in his own box, his limited sense of reality.

I will not pretend that I begin to grasp the scientific implications of Einstein's idea. But in my amateurish browsing, the most lucid explanation I have seen is in Jacob Bronowski's "The Ascent of Man," where a colleague steered me to these words:

"For Newton, time and space formed an absolute framework, within which the material events of the world ran their course in imperturbable order. His is a God's eye view of the world: It looks the same to every observer, whereever he is and however he travels.

By contrast, Einstein's is a man's eye view, in which what you see and what I see is relative to each of us, that is, to our place and speed.And this relatively canot be removed. We cannot know what the world is like in itself, we can only compare what it looks like to each of us, by the practical procedure of exchanging messages."

I was stunned by those sentences, for Bronowski had captured the core of why Einstein speaks directly to the modern condition. If we knew this to be true about ourselves, if we absorbed a new reality based on Einstein's would alter all of our affairs, feelings, expectations, demands, grievances. Families, nations, life itself would seem different to us, more complicated certainly, but also more human. For Einstein's idea parallels the modern experience, both the irrationality and the technological magic of modern life. This new condition is difficult to accept. It makes us feel simultaneously less noble, less powerful than the Enlightenment version of mankind but also more liberated to explore, freed from the social gravity of history.

If we can imagine Einstein's idea symbolized by a beam of light, I think of Hitler's idea as a furious machine -- a complex thing of many moving parts, powerful and efficient, demanding perfect synchronization, dismissing irrelevant realities, insisting on its own perfection.

Hitler's fascism raised a god-like social vision, a self-exalting sense of history. This single nation could so order its affairs, its own people, and impose its authority on lesser beings, other people, to achieve a kind of immortality. Hitler's vision insisted that Nazism was at the center of time and space, the absolute arbiter of reality, which claimed the moral obligation to impose its reality on all others.

The furious machine ended in destruction, of course, and Hitler's particular vision was universally renounced (though many of his totalitarian techniques of efficiency and moral authority seem to endure). My point is this: The life of nations and indeed, of individuals is still guided largely by the fallacy of self-centered certitudes which Hitler exalted to the ultimate tragedy. His legacy is the arrogant self of modern life, the technological illusion that one controls time and space, if only one organizes efficiently. The children of Hitler would not build concentration camps or murder Jews, of course, but they do organize reality for all of us, according to principles which have been disproved, which the children of Einstein understand, dimly at least, to be wrong. Each of us, whether we choose to admit it, carries a piece of both legacies in our souls.

If Hitler's children are following dead principles, refuted by history, the children of Einstein are still struggling with new experiences, not yet translated into governing ideas. For now, we can only speak confidently of our new experiences and what they might imply. Video images enlarge our imaginations, routinely carrying us back and forth around. the world. Space exploration takes us beyond this world's time and makes us imagine competing centers of reality. The computer extends our thoughts and allows us to manipulate gross data and elegant abstractions which exist beyond our own experience. Children born and raised with video stimulation seem to adapt much more comfortably to the abstractions of the computer, which suggests that they do not observe reality in quite the same terms as those who grew up before television.

I thought of Einstein's beam of light last year when we were all enthralled by the international video theater of the Iranian seizure of American hostages. The electronic images, relayed through space, conveyed a kind of clamoring dialogue between two societies, one wealthy and powerful, one poor and struggling, speaking different languages and, indeed, speaking from different time machines at different points of history. It was almost as if modern Christians were, by magic, permitted to communicate with their own ancestors, the Counter-Reformation of Western Europe, for, as historians have observed, the present-day Islamic revival resembles in many ways the turmoil which western Christianity experienced 400 years ago.

And what did any of us learn from that strange exchange? Not very much, I think. But there were whispers of reality that must have filtered through. The suggestion that power alone would not alter the fundamental distance of time and perception. A hint at least that the modern world will draw us into more and more uncomfortable conversations in which our idea of reality, the self-centered truth, is frustrated by competing realities. And a question from Einstein: Is it possible that across this permanent relativity of time and space, people may at least learn to send intelligible messages?

Finally, I hear echoes of Einstein in modern literature, more specifically in the novels called "post-modernist," in which time and action whirl this way and that, back and forth between ancient legend and space-age adventure. The most accessible of these, the best novels of Kurt Vonnegut, make a standing cosmic joke of our dizzy reality. A visitor from earth is trapped on a distant planet, held in a cage like an animal from the zoo. Meanwhile, he is obsessed by an earthly memory of the Dresden fire bombing. The story dances playfully back and forth from one reality to another in a way that seems ridiculous and true.

The post-modernists seem obsessed with something they have discovered, a technique of [WORD ILLEGIBLE] within-fiction which conveys to the willing reader a new frame or reference: truth-within-truth, each character trapped in his own box yet forced to interact with other characters, other boxes, other worlds.

In the vaguest terms, I would say this "beam of light" will lead to a new definition of self, a new sense of human empathy, a deeper grasp of relations among individual, not to mention among nations. If people learn to think differently, then eventually they will behave differently. But empathy does not require one to deny self-interest, only to understand that those unalterable differences of time and space exist. Indeed, empathy suggests a form of power in itself that increases our ability to control events rather than be controlled by our own illusions. That is the inheritance from Einstein, if only his children will grasp it.