The yoga system conceived by Pataïjali is referred to herein. In the Yoga-sütra of Pataïjali, the soul is called pratyag-ätmä and parag-ätmä. As long as the soul is attached to sense enjoyment, it is called parag-ätmä. The soul is subjected to the functions of ten kinds of air at work within the body, and this is perceived through the breathing system. The Pätaïjala system of yoga instructs one on how to control the functions of the body's air in a technical manner so that ultimately all the functions of the air within become favorable for purifying the soul of material attachment. According to this yoga system, pratyag ätmä is the ultimate goal. This pratyag ätmä is a withdrawal from activities in matter. The senses interact with the sense objects, like the ear for hearing, eyes for seeing, nose for smelling, tongue for tasting, hand for touching, and all of them are thus engaged in activities outside the self. They are called the functions of the präëa-väyu. The apäna-väyu goes downwards, vyäna-väyu acts to shrink and expand, samäna-väyu adjusts equilibrium, udäna-väyu goes upwards—and when one is enlightened, one engages all these in searching for self-realization.