Sound, touch, form, taste, and smell are the five sense objects corresponding to the five sense organs: the ears, skin, eyes, tongue, and nose. The mind has a natural tendency to be led astray by these sense organs. Our scriptures abound in warnings against attachment to sense objects. The Vivekachudamani (77) says: "Sense objects are even more virulent in their evil effects than the poison of a cobra. Poison kills one who takes it, but sense objects kill even those who look at them through their eyes."
What is implied here is spiritual death. How sense objects lead to spiritual ruin is described in the Bhagavad Gita (2.62-3): "When a man dwells on sense objects, he feels an attachment for them. Attachment gives rise to desire, and desire breeds anger [toward the obstacles thwarting its fulfillment]. From anger comes delusion; from delusion, the failure of memory [regarding what we have learnt from the scriptures, our teacher, and past experience]; from the failure of memory, the ruin of discrimination; and from the ruin of discrimination the man perishes [in a spiritual sense]."
The Vivekachudamani (176) compares the mind to a huge tiger prowling the forest-tract of sense pleasures, and warns those with a longing for liberation to stay away from the forest.
The Ashtavakra Samhita (2) has valuable instructions for a spiritual aspirant: "If you aspire after liberation, my child, shun the objects of the senses as poison and seek as nectar forgiveness, sincerity, kindness, contentment, and truth."
Sense objects are not always outside-our mind can create them from the impressions within. Some people may abstain from sense enjoyment temporarily because of illness or bereavement. But such abstinence is of no value, since the desire for enjoyment lies buried within: "The objects of the senses fall away from a man practicing abstinence, but not the taste for them. But even the taste falls away when the Supreme is seen." (Bhagavad Gita, 2.59)
The mind needs something to hold on to all the time. Taking the line of least resistance, it holds on to the sense organs and their objects. But such a hold is dangerous for a spiritual seeker because if the mind yields to even one of the turbulent senses, it carries away discrimination even as a gale carries away a ship on the waters. (Bhagavad Gita, 2.67)
How then to free the mind from this stranglehold of the senses? The way is to fill the mind consciously with thoughts of God, repeat God's name with longing and devotion, and meditate on a divine form. Meditation on a divine form gradually reduces our attachment to our own body and that of others. The more we move toward the east, says Sri Ramakrishna, the more the west is left behind. He teaches that the way to discipline the mind is to give its natural impulses a Godward turn: "One cannot completely get rid of the six passions: lust, anger, greed, and the like. Therefore one should direct them to God. If you must have desire and greed, then you should desire love of God and be greedy to attain Him. If you must be conceited and egotistic, then feel conceited and egotistic thinking that you are the servant of God, the child of God."