What is the meaning of the term “yoga” as it is popularly used today? First, how much has the yoga landscape changed over the last two millennia? The short answer is that much is the same, and there are some differences. The practices for increasing sattvic, or pure, qualities are known collectively as yoga. Yoga, the tradition with which Sankhya is paired, still sets out the principles of discipline required for achieving liberation.

The methods of yoga are called sadhanas. The different methods to achieve liberation remain, such as hatha yoga, kundalini yoga, mantra yoga, jnana yoga, karma yoga, and bhakti yoga. The means to the ends, therefore, are much the same as ever.

Yoga developed in special ways, especially by the tantric schools of the Middle Ages. The “yoga of dissolution,” laya yoga, is often identified with hatha yoga, based on ancient Indian physiological notions that play a major part in the form of yoga taught by Western practitioners. Hatha yoga emphasizes the importance of physical means, such as special acrobatic exercises and very difficult postures, and sometimes advocates sexual union as a means of salvation.

Kundalini Yoga and Chakras

In kundalini yoga, the body is thought to exist within a field of energy that is most concentrated in the seven major chakras(wheels), that is, subtle centers along the chief vein of the body, known as susumna(channel).

In the first chakra, muladhara, the lowest “wheel,” behind the genitals, is the kundalini, the “serpent power,” which is generally in a quiescent state. By yogic practices, however, the kundalini is awakened, rises through the susumna, passes through all the seven “wheels” of psychic force, and unites with the topmost, sahasrara. By awakening and raising his kundalini, the yogi gains spiritual power, and by uniting it with sahasrara, he wins salvation.

The sadhaka, or devotee, in the tantric rite imagines the divine power (shakti) asleep within him, coiled away like a sleeping serpent (kundalini) at the root of his spine. While carefully controlling his inhalations, the sadhaka breaths deeply first through one nostril and then the other (pranayama), to clear the way for the kundalini in the spiritual channel. He then thinks of her as aroused; she lifts her head and begins to move up the susumna, touching a number of “centers” or “lotuses” (the chakras) regarded as the seats of the elements of the body. The muladhara is the seat of “Earth”; it is pictured as a crimson lotus of four petals.

The second chakra, called svadhisthana(Shakti's own abode), is at the level of the genitals and is the seat of the element water. It is often depicted as a vermilion lotus of six petals.

The third chakra lies at the level of the navel and is known as manipura, the city of the lustrous gem, so called because it is the seat of element fire. It is sometimes pictured as a blue-black lotus of ten petals. According to the psychology of this system of lotuses, muladhara, svadhisthana, and mani-pura are the centers from which the lives of most people are governed.

Superior Centers

The rest of the centers are superior centers. The fourth chakra lies at the level of the heart, and is the lotus in which the first realization of the divinity of the world is experienced. Here, the god reaches down to touch his devotee.

The fifth chakra, ether, the ultimate element in the universe, is a smoky purple hue and is made of sixteen petals, at the level of the throat. This is the visuddha chakra, which means “the completely purified.”

The sixth chakra is called the third eye. Beyond this point between the eyebrows, is the lotus of command (ajna), where the mind is free of limitations. This is when the devotee sees the Lord. It is considered the center that manifests the power of the will and allows spiritual insight.

The seventh chakra, the crown, is considered the seat of cosmic consciousness. In its fully opened state, it is perceived as a thousand-petal lotus effulgent with light. The tantric worshipper is supposed to imagine himself as having purified his body by suffusing all the lotuses with the awakened kundalini in this way.

The awakened kundalini gives the yogi superhuman power and knowledge, and many yogis have practiced yoga for this rather than for salvation. Some adepts of this form of yoga have developed powers that cannot fully be accounted for by modern medical science and that cannot be explained away as subjective, but the physiological basis of laya and hatha yoga is certainly false; there is no physical kundalini, susumna or sahasrara.

As A. L. Basham exhorts, “The ancient mystical physiology of India needs study, not only by Indologists, but by open-minded biologists and psychologists, who may reveal the true secret of the yogi.”