Except by the experience of the self, the hankering for objects will not go away. When the hankering for the sense-objects does not go away, the senses of even a wise man, though he is ever striving to subdue them, become refractory, i.e., become violent and carry away perforce the mind. Thus, the subduing of the senses depends on the vision of the self, and the vision of the self depends on the subduing of the senses. Consequently, i.e., because of this mutual dependence, firm devotion to knowledge is difficult to achieve.