Sigmund Freud, Carl Jung and Alfred Adler. These three figures loom large in the history of modern psychology, casting long shadows that have, in the course of one century, forever changed the way we use the first-person pronoun, "I." Among these giants, Freud is indisputably the most towering monolith. It was Freud's pioneering use of the term "the I" ("das Ich" in his native German, which was then translated into the Latin "ego") that brought "ego" into common parlance and popular interest to the process of self-consciousness.

What is the ego? What is the "I" or subjective sense of self? How does this unequivocal yet enigmatic fact of our experience as human beings come into being? What is the nature of the "ghost in the machine"? While religion and philosophy have asked these questions for millennia, modern Western psychology has sought to bring a scientific, albeit mechanistic, understanding to the nature of the mind and its workings. Psychology is recognized in the secular world today to be the definitive source for knowledge about the ego. So for this edition of What Is Enlightenment?, we wanted to tap into the original wellsprings of modern psychology—or at least come as close to them as we could.

Sigmund Freud, with extraordinary passion, ingenuity and insight, was intent on acquiring scientific certainty about the essence and activity of the ego, which he believed could be attained only by isolating the various phenomena of the mind and consciousness as mechanisms. The repercussions were revolutionary. In his more than fifty years of groundbreaking research into the human psyche, Freud elaborated a network of theories about the many currents and crosscurrents below the surface of the human personality—the conscious and unconscious; the ego, id and superego; the libidinal and aggressive drives; the Oedipus and Electra complexes; the defense mechanisms—that have become inextricably interwoven in the fabric of modern thought. We now know that there is far more to the "I" than meets the eye.

How we view the "I" seems to color how we view everything. Our understanding of the "I," the ego, is perhaps the first and closest lens, the first film against the cornea, through which we look at our experience and at what it means to be a human being. For Freud—immersed in the dynamic tensions and countertensions within the psyche that he believed made man unique among the animals and enabled the self-interested compromise that we call human civilization—the ego is constantly buffeted by opposing forces and does its best to negotiate them all. "The poor ego . . . serves three severe masters and does what it can to bring their claims and demands into harmony with one another. No wonder that the ego so often fails in its task," he writes. Freud's therapeutic aim was the courageous and fully conscious acknowledgment of this harsh reality of the state of man, and it was this that he felt would facilitate his highest vision of psychological health: the "transformation of neurotic misery into common unhappiness."

Psychoanalysis—Freud's innovative treatment method in which the patient is encouraged to speak freely about memories, associations, fantasies and dreams and which relies on Freud's theories of interpretation—was Freud's noble cause and, for a time, it was Alfred Adler's and Carl Jung's as well. Alfred Adler, a medical doctor with a deep interest in psychology and human nature, met Freud in their native Vienna in 1900 at a medical conference where Freud presented his new theories about dreams and the unconscious. Freud's radical ideas were met with scorn and open hostility—as they often were during these early years of the psychoanalytic movement. Adler, one of the few who had recognized the brilliance of Freud's first major work, The Interpretation of Dreams, was dismayed by the proceedings and came to Freud's defense in an article he wrote for a medical journal in which he demanded that Freud's views be given the respect and attention they deserved. Adler soon joined the circle of psychologists who gathered at Freud's home on Wednesday evenings for animated discussion, debate and collaboration about emerging psychoanalytic theory. Buttressed by his loyal supporters, many of them insightful psychologists and original thinkers in their own right, Freud's movement grew as his seminal ideas gradually captured the imagination of intellectuals throughout Europe, England and America. Adler was for a time the president of the Vienna Psychoanalytic Association and the editor of its journal. Yet there had always been differences between his own views and Freud's, and over the years, these differences became increasingly apparent—and increasingly problematic. For one, Adler never accepted Freud's views about the overarching significance of infantile sexual trauma. Freud was launching a revolution, however, and there was no room for dissent among the officers. In a dramatic and politically charged break, Adler resigned his posts in 1911, leaving Freud's circle along with a group of eight colleagues to found his own school of psychology. He and Freud never met again.

Adler's school of psychology, which he called "Individual Psychology," was based on the idea of the indivisibility of the personality. His most significant divergence from Freud's premises was his belief that it was crucial to view the human being as a whole—not as a conglomeration of mechanisms, drives or dynamic parts. And in contrast to most psychological thinking of the time, Adler believed that, fundamentally, human beings are self-determined. Central to his therapeutic approach was his belief that people always have control over their lives and make choices that shape them. "Individual Psychology breaks through the theory of determinism," he writes. "No experience is a cause of success or failure. We do not suffer from the shock of our experiences—the so-called trauma—but we make out of them just what suits our purposes. We are self-determined by the meaning we give to our experiences." Adler's emphasis on the wholeness of the person and the fact that our values inevitably shape our experience led to his conviction that, in the end, there is only one true meaning to human life: care and love for our fellowmen. "There have always been men who understood this fact; who knew that the meaning of life is to be interested in the whole of mankind and who tried to develop social interest and love. In all religions we find this concern for the salvation of man." For Adler, it is only this meaning, this interpretation of our experience—and our conscious increasing of fellow-feeling and care for the whole of humankind—that leads to the genuine mental health and happiness of the individual.

Carl Jung met Freud in 1907, after he sent Freud a report on some of his early research in the psychotherapeutic technique of word association, to which Freud responded with an invitation to meet him in Vienna. Jung lived in Zurich, where he was practicing psychiatry and teaching at Zurich University. At that first meeting in Freud's home, the two men talked "virtually without a pause for thirteen hours." Each was captivated by the other's genius and passionate interest in psychology, and they began a close correspondence in which they exchanged letters as often as three times a week. Jung quickly stepped into a leading role in the psychoanalytic movement, becoming a staunch defender and chief disseminator of Freud's ideas. Freud confided to Jung that he saw him as his "successor and crown prince," and Jung became, for all concerned, Freud's heir apparent. From the beginning, Jung found Freud's theories about "repression" and "the unconscious" to be ingenious explanations of much of what he was finding in his work with his own patients. But, as Adler did, he struggled with Freud's insistence on the primacy of the sexual drive.

Yet there was another significant tension between Freud and Jung: Jung's burgeoning interest in world religions, mythology and alchemy, with which Freud had little patience. Religious imagery and occultism had in fact been a recurring fascination for Jung, and he had had several "paranormal" experiences and encounters with psychic mediums during his youth. A major turning point in Jung's intellectual career was his book Symbols of Transformation, researched and written between 1909 and 1912, while he was still Freud's champion spokesman and organizer. Jung immersed himself in world mythology, plunging deep into the subterranean caverns of dream, fantasy and preverbal imagery where all manner of gods and demons dwell. "The whole thing came upon me like a landslide that cannot be stopped," he wrote of his work during this period. "It was the explosion of all those psychic contents which could find no room, no breathing space, in the constricting atmosphere of Freudian psychology and its narrow outlook." In 1914 Jung broke with Freud to develop his own school of psychology, which emphasized the interpretation of the psyche's symbols from a universal mythological perspective rather than a personal biographical one. "The psyche is not of today," he asserts. "Its ancestry goes back many millions of years. Individual consciousness is only the flower and the fruit of a season." For Jung, the aim of life is to know oneself, and to know oneself is to plumb the depths of the inchoate seas of not only the personal unconscious but the collective unconscious as well.

What is the ego? Is it the battered servant of three harsh masters with competing demands, as Freud asserts? Or is it, as Jung suggests, the central complex in the field of consciousness subject to the powerful whims and furies of the vaster unconscious? Or does it make no sense to speak about the ego as separate from the human character as a whole, as Adler insists? Many more names have been added to the pantheon of modern psychology since Freud, Jung and Adler carved out their respective places. Psychologists as diverse in approach and predilection as B. F. Skinner and Abraham Maslow have made ingenious attempts to solve the mystery of the "I" and discover the nature—or debunk the very existence—of the ghost in the machine. More than two thousand years ago, etched into the stone walls of Apollo's temple at Delphi were the words: "Know Thyself." Does Western psychological inquiry take us to the heart of this matter? Or is it, as world-renowned theorist of ego development Jane Loevinger suggested to us, "just an attempt to see the shadows on the wall of Plato's cave"? How close psychology can come to knowing the mysteries of the human heart and soul is perhaps an open question. Yet for this issue of What Is Enlightenment?, we were eager to know what light the leading torchbearers for Freud, Jung and Adler and their schools of thought could shed on our questions about the ego. What follows are three intriguing interviews with passionate exponents of the schools of psychology that forever shaped our understanding of das Ich.