Patanjali's Yoga-Sutra is widely recognized as the most important treatise describing the philosophy and practice of yoga. Written sometime between the 2nd century B.C.E and the 4th century, the Yoga-Sutra outlines Patanjali's eight steps to liberation and self-realization. The work is composed of 196 aphorisms, grouped into four sections. By themselves, the aphorisms do not communicate a great deal to anyone not already familiar with the philosophy and practice of yoga. Consequently, numerous scholars and yogis have written commentaries explaining the significance of each aphorism. Among thes commentaries is I.K. Taimni's The Science of Yoga.
While a commentary probably is necessary for a deep understanding of the Yoga-Sutra, it is difficult for someone new to yoga to know if any particular commentary accurately conveys the ideas of Patanjali. This is especially true in that yoga tradition admits of numerous paths to liberation and self-realization unique to whatever is effective for a practitioner. Under the circumstances, one might reasonably abandon the need to gain an accurate understanding of Patanjali, and simply entertain whatever interpretation seems to make sense, leaving the pursuit of Patanjali's actual views to more advanced scholars.
If one approaches Yoga-Sutra commentary in this fashion, I.K. Taimni's The Science of Yoga is likely to be rewarding to anyone seeking a pragmatic approach to yoga. It will not, however, completely satisfy anyone with a moderately skeptical disposition. Nonetheless, there is much that is worthwhile in the commentary, if one cares to separate the practical, experiential claims from those relying on non-falsifiable claims.
The truely valuable aspects of the work come in the elaboration of Patanjali's eight steps to liberation and self-realization or Raja-Yoga. These steps are yama, niyama, asana, pranayama, pratyahara, dharana, dhyana, and samadhi. Yama and niyama are essentially moral practices. Yama refers to the concerted effort to do no harm. Niyama refers to a set of positive practices that cultivate purity and self-discipline. Asana refers to the yogic practice most well-known around the world, that of assuming physical postures that stretch and strengthen the body. Pranayama is the practice of breath control for the purpose of preparing the yogi for later stages of meditation. Pratyahara refers to withdrawing from the objects of the senses such that one is no longer drawn to pleasures and driven from pains, thereby enhancing one's autonomy.
The last three steps, dharana, dhayana, and samadhi, make up three stages of concentration and meditation. These are the most signficant yogic practices. All others might be seen as preparations for these. It is in the description of these that Taimni's Science of Yoga really stands out. Roughly put, the goal of yoga is to free oneself from the delusions of ordinary life and realize one's true self in union with pure consciousness or the absolute. Yogic practices are attempts to eliminate the obstacles to that supreme spiritual state. The most important obstacles are delusions about the self and its relation to reality.
Dharana is the first stage of meditation, seeking to escape delusions of materialism. Here the yogi meditates on external objects until one recognizes the distinction between the object and the mental impressions of an object. In this stage the yogi has transcended naive realism and simple materialism and thoroughly accepts idealism, rather in line with the metphysics of George Berkeley. A clear self-consciousness brings awareness to the self in a mental state that is distinct from ordinary unselfconscious engagement with the objects of the world. In dharana, the self is separated from the material world.
Dhayana is the second stage of meditation in which the true self is discovered to be yet deeper within consciousness. Just as dharana separated the self from the material world, dhayana separates the self from the impressions that are present to the self. The self is now the observer separate from the observed. More radically, the self is not even the thoughts or ideas that pass into and through one's consciousness, but is that which is afflicted by thoughts and ideas, all alien to the self.
Finally, when the yogi is firmly established in dhayana, she can enter the highest state of consciousness, samadhi, in which "the mind's own form or essential nature disappears, as it were." There are no distractions separating the self from ultimate reality.
Taimni's account of passing through these stages is a remarkably lucid phenomenology of meditation. This alone, makes his complex and detailed 446 page work most rewarding.
Patanjali's Yoga-Sutra contains many aphorisms aluding to the fantastic abilities acquired by advanced yogis, for example, levitation, extrasensory perception, knowledge of past lives, and the ability to take control of the bodies of other people. Despite Taimni's assertions that these claims are founded on sound scientific methods, i.e., the experience of advanced yogis, his case for them is remarkably weak, given that he was a Professor of Chemistry at Allahabad University. It fails on the grounds that these abilities are known to only advanced yogis who, having no interest in the material world, do not show off these abilities. One must take it on faith that the practice of yoga leads to these abilities.
One might argue by analogy that the validity of proofs in extremely advanced mathematics are only known to a tiny number of very advanced mathematicians. The analogy fails, however, in that the extraordinary claims of the yogi are the sort that should be easily demonstrated. That yogis choose not to demonstrate them seems entirely too convenient.
Setting aside these essentially superstitious claims, Taimni's commentary on Patanjali lucidly describes methods that have reliably led countless yoga practitioners to a liberation and self-realization that induces a profound spiritual peace. While yoga is generally associated with Hinduism and the traditions of India, the practice is perfectly compatible with many other religious, philosophical, and spiritual views and traditions. A year or so of practicing the asanas alone is enough to demonstrate its worth to most anyone.