The Yoga Sutras of Patanjali are 196 Indian sutras (aphorisms) that constitute the foundational text of Raja yoga, which is the royal practice of the four main yoga forms. In the Yoga Sutras, Patanjali prescribes adherence to eight "limbs" or steps (the sum of which constitute "Ashtanga Yoga," the title of the second chapter) to quiet one's mind and achieve kaivalya. The Yoga Sutras form the theoretical and philosophical basis of Raja Yoga, and are considered to be the most organized and complete definition of that discipline. The Sutras not only provide yoga with a thorough and consistent philosophical basis, they also clarify many important esoteric concepts which are common to all traditions of Indian thought, such as karma.