Like all genuine questions, the question about identity will never die. Such questions do not have answers, in the sense of a single definitive statement that eliminates the need to ask the question again. Yet that does not mean that talking about such questions is an endless and meaningless game, merely going back and forth over the same positions, more cleverly expressed. Instead, at crucial moments in this long conversation, something emerges that reveals a new truth, perhaps implicit in what has gone before but only now expressed. Because of that insight, everything appears in a new light. Such questions and conversations are living things; they are fascinating because, at any moment, something so compelling may emerge that nothing will be the same again.

At such moments, we realize the narrowness of our preconceptions. Hamlet was right: our philosophy is ignorant of most things in heaven and on earth. As Socrates found out, many people do not easily bear the sting of knowing their own ignorance. He tried to show that this was not hurtful, but helpful, purging our false assumptions and narrow opinions. If there is more than we know, eventually we may know more. In this, modern science should continue Socrates’ controversial project of examining, testing, and improving human opinions through searching conversation and reasoned inquiry. As a young man, Socrates turned away from natural philosophy because it did not inquire into why the world is as it is, and not otherwise.

This question haunted Kepler and Einstein; it should continue to haunt us also. In the story of individuality, contrasting visions confront each other. The individuality of each person and macroscopic object is unique, like Hector’s shining helmet. Yet that helmet, like each of us, is made of electrons that blend and merge. The world as we experience it calls us to reconcile these views; vast numbers of identical beings can form structures whose complex configurations give them the appearance of uniqueness. Here we return to the question raised throughout this book, whether the individuality of persons really touches the individuality of things. I may be like the ship of Theseus, a phantom haunting itself, for on the atomic level I have no individuality.

Because of this lack of individuality at the quantum level, it may be important to maintain the sense of strangeness that separates the quantum realm from the human. The mind all too easily assimilates the world into itself, while ignoring what may be truly foreign. If that is so, it is strangely beautiful that human individuality rests on anonymous quanta.

Nevertheless, it is possible to find certain correlates between human experience and this radical merging of individuality. Human individuality is more like a field than isolated, atomic selfhood. If Jean Piaget is correct, each of us begins with no firm limit between our self and the “outside” world. Perhaps one might be able to touch again some of that original wholeness. Lucien Lévy-Bruhl used the phrase participation mystique to describe the ardent investment of the self in another object or person,as when a Zuñi dancer becomes the god whose mask he wears: “To exist is to participate. . . . Without participation, one has no existence.” Human identity emerges in the intense identification that Lévy-Bruhl calls participation.

In this view, what we feel is not so different from the behavior of our electrons, whose resonance and interference reflects their shared identicality and perhaps ours also. Crowds of people experience such moments of constructive or destructive collective feeling, merged in ecstatic communion or blood lust. But even when solitary, one can experience the truth of Walt Whitman’s observation, “I contain multitudes.” Sometimes the boundaries of self seem to expand past the limits of self-interest. My sphere of concern grows and shrinks in a way that suggests that I do not end at the edge of my skin, but may extend outward into other persons, other things. At one extreme is the utter destruction of self that is psychosis. Yet even in more tempered moments, the self merges into someone or something beyond itself.

Looking out his window, John Keats felt identified with the sparrow pecking at the ground outside: “I take part in its existence and pick about the Gravel.” Poetry and music call us beyond the narrow limits of the self and so does science. Here Spinoza’s vision may be the closest: each individual is really a mode of a single universal substance, the field. Feeling the complex interweaving of identity that joins us, each of us may be an aspect of the other. Such attenuation or extension of identity is crucial to love, but it also marks the smallest movement of attention or imagination that stirs the self. If identity is found when it is lost, it may be regained when surrendered. In that case, the strange identity of electrons may give us an image of our own inwardness. Imagine, then, two snowflakes on a winter evening. Consider you and me. Consider us.

Peter Pesic, Seeing Double: Shared Identities in Physics, Philosophy, and Literature