WHAT IS IMPRESSION?
A whirlpool or thought-wave arises in the mind-ocean. It operates for sometime. Then it sinks below the threshold of normal consciousness. From the surface of the conscious mind wherein it was uppermost for some time, it sinks down deep into the region of the subconscious mind. There, it continues to be a subliminal action and becomes an impression.
A conscious action-whether cognitive, affective or conative assumes a potential and hidden form just below the threshold of consciousness. This is termed an Impression.
MEMORY – A REVIVAL OF IMPRESSION
The impressions are embedded in the subconscious mind or Chitta. The subconscious mind is otherwise known as the unconscious mind. Subjective mind, subconscious mind, unconscious mind and Chitta are synonymous terms. The seat of this subconscious mind is the cerebellum or hindbrain. You can recall the past experiences from the storehouse of Impressions in the subconscious mind. The past is preserved even to the minutest detail. Even a bit is never lost.
When the fine Impressions come up to the surface of the conscious mind back again as a big wave, when the past comes back to the surface of the conscious mind again by recollection, it is called memory. No memory is possible without the help of Impression.
HOW THE IMPRESSION IS FORMED
An experience in the sense-plane sinks down into the depths of the subconscious mind and becomes there an Impression. An Impression of an experience is formed or developed in the subconscious mind at the very moment that the mind is experiencing something. There is no gap between the present experience and the formation of an impression in the subconscious mind. A specific experience leaves a specific Impression. The memory of this specific experience springs from that particular Impression only, which was formed out of that particular experience.
When you perceive an orange and taste for the first time, you get knowledge of an orange. You know its taste. You know the object, orange. An Impression is formed in the subconscious mind at once. At any time, this Impression can generate a memory of the object, orange and knowledge of an orange. Though the object and the act of knowledge are distinguishable, yet they are inseparable.
CYCLIC CAUSATION OF THOUGHT AND IMPRESSION
An object awakens or revives Impressions in the mind through external stimuli. Hence, a thought arises subjectively from within, without a stimulus from outside. When you think of a cow which you have seen before, you repeat the word cow mentally. Then only, the mental image comes. Then, a thought is formed. Impression causes thought, and thought causes Impression, just as seed is the cause of the tree, and tree is the cause of the seed, in turn. There is cyclic causation on the analogy of seed and tree.
This cycle of thought-wave and impression is beginningless, but has an end when one attains Divine Knowledge and liberation. They get dissolved into Nature. They cease to produce any effect on the Soul. Impression should be fried up by continuous Samadhi. Then only you will be free from births and deaths.
Mind – Its Mysteries and Control by Sri Swami Sivananda