This essay is excerpted from the opening chapter of The Soul, a new book by Rabbi Adin Even-Israel Steinsaltz. Read more about the book, and a longer sample, here.
We have a soul. We know because we can feel it.
It is unclear how early in his life a person discovers he or she has a soul; probably not during infancy, and maybe not even in early childhood. In any event, this is one of the first things a person perceives, even if he does not perceive it fully. This is similar to our perception of our bodies, which also develops gradually: At first it includes only the visible, or the most active parts, of the body. This perception, however, continues to expand with time and experience. One can assume that an infant discovers his body through the sensations he encounters in various body parts, perceiving it through individual experiences that gradually combine to form some sort of whole. He may initially discover that he has a stomach, since he sometimes senses pain there. Through his sense of sight and his other senses, he slowly discovers that he also has hands, feet, and other body parts, until he attains a consciousness of his entire body. But despite the fact that we conduct a constant, loving dialogue with the body (possibly too loving!) and are always dealing with it and caring for it to some degree, more of it is hidden from us from us than perceived. While we are able to see and touch the external parts of our bodies, our acquaintance with its inner workings is indirect and limited, assuming we are acquainted with these at all. Most people don’t know the exact location of their heart, and, surprisingly, not even their stomach. They are certainly unfamiliar with other body parts that they might never even have heard of.
The experience of the soul does not enter our consciousness as a complete, unified perception either. It penetrates our consciousness as an accumulation of varying experiences: Love and hate, attraction and abhorrence, curiosity and learning, and so on. These experiences appear individually. Only at a later stage do they form some sense of self, of an “I.”
When the totality of these experiences is defined as “I,” even an unsophisticated person can, to some extent, differentiate between “I” in the physical sense and “I” in the spiritual sense, meaning the soul. However, just as our acquaintance with our bodies begins with externally focused perceptions, our acquaintance with our souls also begins with outwardly focused experiences, while its inner workings are far less apparent. Even adults are not entirely familiar with them and are generally incapable of describing them precisely.
Nevertheless, our acquaintance with the soul is a fundamental one. The recognition of the soul and the experiences revealing it exist within us even before they are expressed verbally, yet a child needs to reach a certain level of maturity to be able to speak of his soul. This is because profound, spiritual experiences become apparent to us only in extraordinary circumstances, and even then, they are not understood completely as part of a larger and meaningful structure .
The soul is something we sense. We are as certain of its existence as we are of the body’s existence, but we don’t know much about it. Throughout the ages, various attempts have been made to locate the soul spatially. The Greeks thought that the locus of the soul was in the diaphragm. By contrast, the Torah states that “the blood is the soul” (Deuteronomy 12:23). This perception is perhaps related to the idea that the heart is the basis of physical existence as well as the focal point of the soul.
All of these efforts are merely attempts to resolve this enigma by locating the soul somewhere in the body. Nowadays, after many generations of observation and experimentation, it is generally accepted that the soul’s location is in the brain. However, scientists and philosophers as well as other thinking people know that this sort of definition is merely convenient shorthand and not really an accurate description. Even those who locate the soul in the heart or brain know that these organs are just pieces of flesh that can, at best, serve as points of contact with the soul but do not constitute the soul itself.
Some are more inclined to contemplate the essence of their souls, while others can live their entire lives – even lives of profound intellectual activity – without taking an interest in their souls at all, or even without giving their souls any thought whatsoever. Aside from emerging out of differences in personality, these differing attitudes are also influenced by a person’s inner world of experiences. Those whose lives are externally centered – whether they are preoccupied with physical activity, or even with spiritual matters, whether abstract or practical – do not give their own souls much thought. To them, their soul is a reality that there is no point thinking about.
The more a person is aware of inner experiences such as love and hate, hope and despair, the greater the chance that these experiences will awaken some sort of awareness of the full depth and breadth of the soul. But even people who are more self-aware, who spend at least some time thinking about their souls, do not usually reach beyond the scope of their existing experiences. For example, nowadays, many psychologists, who should theoretically speaking be experts on the soul (the word psyche in Greek means soul, and the term psychology means knowledge of the soul), vociferously declare that they do not believe the soul exists, although they are supposedly dealing with various aspects of it. Psychology offers different theories regarding the interaction of the psyche’s components, but it doesn’t attempt to examine the soul. Even psychologists who posit the existence of a soul are mostly focused on healing it, and, not unlike various kinds of doctors, their main specialization is its various diseases and ailments, not the soul itself.
The statement of the great sixteenth-century philosopher Maharal to the effect that in one way or another, we all sense our soul and know that it exists, yet we do not know what it really is, is relevant here. It is specifically those who spend time exploring the soul who understand that although they are familiar with the layers and parts of the soul, and even with its functions, they are still unable to perceive its essence. They are aware that they are dealing with superficial manifestations of its existence and not with its ultimate nature. It has been said of God that He is “the closest being and yet the most distant being”; so too the soul.
In addition to all of the soul’s functions and capabilities, there is a simple and essential perception of an “I.” However, this perception, which is more basic than and prior to any other perception or thought, has no content; it is merely a declaration. The soul announces “I” at almost every opportunity, but this “I” is never really defined. Our acquaintance with our souls, as familiar and intimate as it may be, is essentially no different from our acquaintance with other people. We might know what clothes they wear, we recognize their physical appearance, or even their way of thinking, but despite this, they are still foreign entities that are familiar to us only through their extrinsic features, not their inner content. A person’s mind contains millions of details, most of which are unknown to anyone else and are unlikely to ever become known to any of them, but the “I” awareness always remains beyond these details, even when he or she makes an effort to become aware of it. “I know,” “I think,” “I feel,” and even “I am alive” are manifestations of the “I” awareness, but they cannot bring a person closer to real familiarity with his or her essence.
Every person has a soul. There are people whose soul reveals itself to them to a greater degree than others’ souls do, but only a few individuals, to whom mysteries beyond intellectual consciousness have been revealed, can speak of the essence of a soul at all. The content of this book draws on the illumination of, and is written in the spirit of, those true masters of the , great sages who were aware of and connected with their divine soul, and, having been party to such knowledge, have conveyed some of its mysteries, and revealed parts of its essence to us.
 The tradition of Jewish mysticism divides the human spiritual realm into several ascending levels. Nefesh is the lowest of these levels, something akin to a basic life force shared by humans and sentient animals alike. The word “soul,” which is a translation of the Hebrew term neshama, is exclusively human. These notions will be referred to throughout the book, although the precise relationship between the nefesh and the soul, i.e., the neshama, is complex and is not dealt with at length here.
 This book discusses and contrasts three basic elements: The nefesh, the “I,” and the soul. The chapter “The Soul, the Nefesh, and the ‘I’” discusses the first two, and the chapter “The Souls within Man” contrasts the nefesh and the soul.
 The term “spiritual” will be used throughout this book to refer generally to all matters related to the soul.
 The Maharal was a preeminent Jewish philosopher of the sixteenth century. This comment of the Maharal’s appears in the introduction to his work Gevurot Hashem.
 Rabbeinu Baḥya ben R. Yosef Ibn Pekuda, ḥovot HaLevavot, Sha’ar HaYiḥud, chapter 10. Rabbeinu Baḥyei was an early Jewish philosopher of the geonic period.
 “masters of the soul” will henceforth appear as the upper case “Masters of the Soul,” and refer to these teachers.