Control over five senses is a difficult notion but is easy to comprehend if we start with the fundamentals. Human beings have five sensory organs: sight, sound, smell, taste and touch. Our mind and body depend on these five senses for the information of the outer world. With the relevant information’s supplied from these five organs our body functions through movement of muscles or release of chemicals in the bloodstream to activate any sensors. The inputs given by the sense organs make our mind feel the emotions of joy, excitement, apprehension or desire. The mind is not in contact with the outer world by itself. If the five sense organs give the information of the outer world to the mind then the individual reacts to it sometimes he is trounce by panic, rambling with delight, overjoyed by excitement, bewildered by anxiety, unsteady by desire and so on. If we do not have a suitable method to filter and control the inputs from the five senses then our mind will have to bear the consequences of all the worldly experiences. So without the help of the five sense organs our mind is cut off to the outer world. It is near impossible for us to cut off the five sense organs from the world.
Even though the five senses is outwardly focused, it is our mind which will be enthusiastic to the information provided, for instance if we are on the way to attend the funeral of a close relative and we happen to pass by a place where a film shooting unit is picturising a song sequence where the actress is clad in skimpy dress, even though our eyes are seeing the event does our mind which is engrossed in the thought of the death of the relative interested? No, why? Just because it is not in a position to entertain the inputs provided by the sight.
Once Veda Vyasa and his son Sukha Muni walked past a river. There were many young girls taking bath in the river. When they saw Sukha Muni, they continued to bathe, without any shyness. But the moment they saw Vyasa, they hastened to cover themselves with clothes.
Vyasa was old man but Sukha Muni was youth. Vyasa was surprised by their act and asked them why they did so. The girls replied that they had to cover themselves in the presence of a man. Then what about Sukha Muni, who had just passed by, Vyasa wondered and wanted to know. Why had they not covered themselves when Sukha Muni had passed by?
The girls replied that Sukha Muni would not notice that which is outside, for he saw nothing but would be engrossed in Self. But Vyasa had his five senses beaming to the outer world and so they had to cover themselves up. Vyasa himself was a great sage. And yet even could not attain the state which his son had reached, namely Indriya Nigraha, control over senses and was not in a position keep his eye sight away from the body of the young girls. Sukha Muni was in this sense superior to his father.
To ensure avoidance of unwanted inputs to our mind from our five sense organs, we need to develop a system that filters and controls the input. This control system which Patanjali Maharshi explains in the Yoga Sutras is Indriya Nigraha, an ability to shut out or restrain from the information and related instinctive reactions from the five sense organs at our choice.