The word yoga comes from a Sanskrit verbal root meaning "to yoke, harness" and in general refers to one or another of the many psycho-physical techniques in Indian religions designed to obtain discipline and control over the body and mind. In its classical contexts, yoga could refer to any one of a whole variety of such self-disciplinary practices. In India, yoga transcended sectarian boundaries. There are, for example, both Hindu and Buddhist forms of yoga and within each of these religious traditions many different kinds of spiritual methods and practices are designated by this term. None of these "yogic" methods is solely physical. All entail some form of mental discipline, which can be labeled meditation; in Indian religions yoga and meditation almost always went hand in hand. The physical practices of yoga were usually seen at best to be only preliminary to the more spiritual forms of yoga that utilize various kinds of meditation techniques.
It is possible that yoga goes back to the earliest period of Indian history. Figurines and seals found at sites of the Indus Valley civilization, dating back to the second millennium B.C.E., have sometimes been interpreted to indicate the practice of yoga there. In particular, one seal depicts what appears to be a deity sitting in a posture typical of later yoga. In the earliest Sanskrit texts of the Vedic period (c. 1500–1200 B.C.E.) there are references to ascetics and ecstatics called muni s ("silent sages") who are depicted with long hair, are said to be "girdled by the wind" (meaning, possibly, naked), and are described as having some of the superhuman powers later associated with advanced yoga practice. The Atharva Veda mentions a group called the vratyas who practice asceticism (they are said to be able to stand for a year) and assume other physical postures as part of their disciplinary regimen. They also seemed to have practiced some kind of breath control and envisioned correlations between their bodies and the cosmos. Also already in the Vedic texts we encounter the theory and practice of tapas or "ascetic heat" which, when obtained by the practitioner through various methods of physical and mental asceticism, was said to impart similar powers and spiritual purity. Tapas was in later texts to come to the forefront of the essential disciplinary practices that were involved in yoga.
By the time of the later texts of the Vedic period, the Upanishads of the third or fourth centuries B.C.E., the word and conceptualizations of yoga are encountered frequently. In these texts, yoga means primarily the control of the mind and the senses. The senses are likened to horses which must be "yoked" or "disciplined" by the yogin (yogi) whose "mind is constantly held firm" and whose "senses are under control like the good horses of a charioteer.… They consider yoga to be the firm restraint of the senses. Then one becomes undistracted" (Katha Upanishad 3.6; 6.11). In these texts some of the physical practices of yoga are also described. The practitioner is advised to retreat to a pleasant place in the wilderness where he should assume a particular physical posture (or asana) and "breathe through his nostrils with diminished breath" (the practice of breath-control called in later yogic texts by the name of pranayama). Yoga is defined in one such Upanishad as "the unity [another possible translation of the word "yoga"] of the breath, mind, and senses, and the relinquishment of all conditions of existence" (Maitri Upanishad 6.25). As the yogin progresses in his practice his body and mind are said to change: "Lightness, healthiness, freedom from desires, clearness of countenance and pleasantness of speech, sweetness of odor and scanty exertions—these, they say, are the first stage in the progress of yoga" (Shvetashvatara Upanishad 2.13). The final stage of the practice, the goal of yoga, is also depicted in the Upanishads—and will become standard in later yogic texts. It is nothing less that the state of deathlessness or eternal life, often imagined in a body of light that never degenerates or grows old.
Yoga was systematized in different ways in two foundational texts dating to around the turn of the Common Era. In the first of these classical treatises, the Bhagavad Gita or "Song of the Lord," yoga is used to describe three apparently distinct but practically interrelated "paths" or spiritual methods. The first of these is called jnana yoga or the "yoga of wisdom." This path consists of deep contemplation on the nature of reality and recognizing the difference between the phenomenal world of change and the unchanging self. Through such meditation, the yogin penetrates the illusory nature of appearances and realizes the ultimate unity of all things and beings. As the Gita is also a theistic (or pantheistic) text, jnana yoga also entails recognizing God or Krishna in all things.
The second kind of yoga in this syncretistic work is karma yoga, the yoga of action. This method is one of "doing one's duty" as it is laid out by the strictures of caste and stage of life (and not renouncing action in the world as seemed to be required by the earlier Upanishadic treatises). Such worldly activity must, however, be performed in a "yogic" and self-disciplined way. While one cannot avoid action, the yogin should act not out of desire for the fruits of action but rather in a desireless and self-sacrificial way. Renouncing the ends or goals, the practitioner of karma yoga was to perform desireless action dedicated to God. The third yoga outlined in the Bhagavad Gita was termed bhakti, "devotion," and was nothing other than the "yoking" or "union" of the self and God. It is depicted as the easiest of the three methods but also the most efficacious.
The other text of this period to synthesize yoga was the Yoga Sutra of Patanjali. Patanjali defines yoga as the "cessation of the turnings of thought," that is, the purification and becalming of the mind and the correlative attainment of higher states of consciousness. Yoga for Patanjali involves eight "limbs" or parts (ashtanga), each one leading to the next and culminating in release from suffering and rebirth.
The first two limbs provide the ethical foundation thought to be necessary for any further progress in yoga. The first consists of the five "moral restraints" (yama s): nonviolence, truthfulness, not stealing, chastity, and the avoidance of greed. The second limb, the internal "observances" (niyama s), provides a second set of five virtues the practitioner should perfect. These are mental and physical purity, contentment, tapas or the practice of austerities and asceticism, the study of sacred texts, and devotion to the "Lord" (God or the guru).
The third part of Patanjali's eightfold path consists of the physical postures or asana s. When the yogin has disciplined his or her moral life, the next step is to discipline the physical body. The later traditions of yoga have greatly expanded this dimension of the yogic path. The physical practices are sometimes referred to as hatha yoga (the "yoga of exertion") and are conceived of in terms of a rigorous program of physical exercise and digestive constraint thought to be preparatory to the more advanced and subtle forms of yoga. Some texts claim there are 840,000 yogic physical postures; a standard list gives 84 including, most famously, the "lotus position" (padma asana). Such postures are designed to make the practitioner's body supple and healthy and help in the general training of self-discipline. Patanjali, however, devotes a mere three verses to the purely physical dimension of yoga, saying only that one should take a position that is "steady and comfortable," for then one is ready to pursue the true goal of yoga, the state of mind wherein one is "unconstrained by opposing dualities."
More subtle than the physical body is the breath, and it is the "restraining of the breath" (pranayama) that forms the fourth limb of the practice. Here again, later yogic texts go into much greater detail about the various practices of breath awareness and control, including methods for retention of the breath over long periods of time. The breath is regarded as the fundamental life force in yoga, and control and manipulation of it is essential for rejuvenating and immortalizing the body. Its power is such that some texts warn about the dangers entailed in the pranayama practices and, as always, insist that the yogin should only practice under the watchful guidance of a master. Patanjali has little to say about it, restricting his observations to the fact that it basically refers to the control of inhalation, exhalation, and retention of breath and that it has as its purpose the making of a "mind fit for concentration."
The next stage of Patanjali's system is named the "withdrawal of the senses" (pratyahara) by which is meant the kind of "yoking" of the sense organs that was likened to the reining in of horses. Another very common image for this portion of the yogic training is that of a tortoise who withdraws its limbs into its shell. So too should the yogin disengage the sense organs from the objects of senses and, by means of such detachment, gain mastery over them. The ability to turn away from the distractions of the object of senses and to increasingly turn attention to the mind itself in a concentrated fashion is, of course, crucial for the meditative pursuits that describe the highest and most subtle forms of yoga.
The sixth, seventh, and eighth limbs of Patanjali's yogic system are progressively higher states of meditative ability and attainment. The sixth is called "concentration" (dharana), defined as the ability to "bind thought in one place" for long periods of time; it is the essence of what is sometimes known as "one-pointedness" of mind. The mastery of concentration leads the yogin to the next the stage of the path, which is called "meditation" per se (dhyana), the unwavering attention of the concentrated mind on the meditative object. The culmination of yoga is the attainment of the eighth limb, pure contemplation accompanied by ecstasy or, otherwise described, the trance-like state of pure "enstasis," which is termed samadhi. The end of the yogic path is defined by Patanjali as "meditation that illumines the object alone, as if the subject were devoid of intrinsic form." The "yogin yoked in samadhi" is, according to a later text in this tradition, completed liberated—free from the "pairs of opposites" or all duality, not bound by the forces of karma, unconquerable, "without inhalation and exhalation," invulnerable to all weapons, and immortal (Hatha Yoga Pradipika 4.108ff.).
Indeed, much of the third chapter of Patanjali's classic text is given over to the extraordinary powers (the "accomplishments" or siddhi s) that are claimed to come along with advanced practice of yoga. These include the ability to know the past and future, the languages of animals, one's previous lives, the thoughts of others, and so on. It is, in fact, said that the perfected yogin becomes omniscient. He or she also attains the power to become invisible, gets the "strength of an elephant," and wins the capability to grow larger or smaller at will. In later texts, abilities such as these are summarized as the eight "great powers" (mahasiddhi s): miniaturization, magnification, levitation, extension, irresistible will, mastery, lordship over the universe, and fulfillment of all desires.
The yoga systematized in Patanjali's Yoga Sutras is sometimes referred to as "classical" or "royal" yoga (raja yoga), especially in contrast to the hatha yoga, which is envisioned as preparatory to the higher spiritual practices of Patanjali's later limbs. It also came to be the charter text of the school of Hindu philosophy (darshana) called "Yoga," which in turn was closely related to the dualistic philosophical school known as "Samkhya" (the main difference being the atheistic quality of the latter, although the "Lord" of the Yoga Sutras is more of a Divine Yogin than a creator god). In these philosophical traditions, the purpose of yoga was understood to be the "distinction" or "discrimination" between material nature and the eternal spirit. The spirit or pure consciousness (purusha) is to be "isolated" from both matter and from ordinary awareness and its afflicted mental experiences. When the purusha becomes thus disentangled, its pure nature can shine forth and the yogin becomes liberated.
The term yoga, as has already been shown, can be applied to a variety of practices and disciplines. Another important use of the term is in the phrase mantra yoga, the "yoga of sacred, efficacious sound." Here yoga refers to the concentration on and repetition of sacred sounds, utterances, syllables, or prayers composed from the Sanskrit language and thought to have inherent transformative power. Such mantras are transmitted from teacher to pupil in an initiatory setting, and it is indeed thought to be primarily the power of the guru that gives the mantra its efficacy. The most famous of such mantras is the sound "om" (sometimes written as "aum" to emphasize the three verbal parts of the utterance) which is regarded as the aural essence of the universe itself. While the texts do claim that mantra yoga will also lead to liberation, it is usually said to be suitable mainly for the practitioner of inferior intellectual capabilities.
Yoga also plays a major role in both Hindu and Buddhist "tantric" or esoteric traditions, which arose around the middle of the first millennium C.E. In Buddhism, tantric practice is divided into four classes, each one regarded higher than the other: action tantras, performance tantras, yoga tantras, and highest yoga tantras. In all forms of tantra, the goal is to transmute the physical body into a body of light, a "rainbow body," through the manipulation of the subtle energies, channels, and power centers (cakra s) of the mystical inner body. This is done through the practices known as guru yoga, the "yoking" of oneself to a tutelary deity or yidam, and the carrying out of a series of visualizations in which one assumes the being of that deity and meditates in that way. There is also a form of "Taoist yoga" in China that bears comparison to the Indian yogas.
Yoga has entered the West mostly as physical exercise and often not as the holistic worldview it was in its original contexts. Increasingly, however, Westerners are aware of the ethical and meditative dimensions to yoga and these elements are finding their way into the practice of yoga outside of India.