Yoga is very much an application of practical psychological knowledge and techniques. The various paths of yoga have each developed an extensive body of knowledge which has been codified into systematic treatment so that someone taking up the practices of a particular path can apply the methods of that path and achieve the desired results over time. Some of the paths, such as Raja Yoga, are well known for their systematic treatment, particularly the organized approach taken by Patanjali. But in reality, whether it is Hatha Yoga or Raja Yoga, or one of the other paths, such as the triple path of Knowledge, Love and Works, experience and long-practice has led to the development of codified methodologies.
Sri Aurobindo describes the situation: “Each path has its Shastra, either written or traditional, passing from mouth to mouth through a long line of Teachers. In India a great authority, a high reverence even is ordinarily attached to the written or traditional teaching. All the lines of the Yoga are supposed to be fixed and the Teacher who has received the Shastra by tradition and realised it in practice guides the disciple along the immemorial tracks.”
This approach provides a relatively straightforward way for the Sadhaka to take up a practice and achieve the result specified. In its essence, however, it has the limitation of any established framework of knowledge, namely, that it tends to restrain or hold back new developments or practices through its naturally conservative tendency.
Sri Aurobindo acknowledges the benefits of this scientific codification of the practices and methods of yoga, but at the same time he makes it clear that there must still be room for free development and experimentation to continue. “The general knowledge on which the Yoga depends is fixed, but the order, the succession, the devices, the forms must be allowed to vary; for the needs and particular impulsions of the individual nature have to be satisfied even while the general truths remain firm and constant.”
Sri Aurobindo, The Synthesis of Yoga, Part One: The Yoga of Divine Works, Chapter 1, The Four Aids, pp. 49-50