In logic perception is to be regarded as a form of true cognition. Taking it in this sense, some Naiyayikas define perception as a definite cognition which is produced by sense object contact and is true or unerring the perception of the table before me is due to the contact of my eyes with the table, and I am definite that the object is a table.
The perception of a distant figure as either a man or a post is a doubtful and indefinite cognition, and, therefore, not a true perception. The perception of a snake in a piece of rope is definite but false; and so it is different from valid perception.
The difmition of perception as a cognition due to the stimulation of our sense organs by the perceived object is generally accepted by us. It is accepted also by many systems of philosophy, and Western.
Some Naiyayikas, the Vedanta’s and others, reject it on the ground that there may be perception thought sense-object contact. God, we are told, perceive all, but has no senses when I see a snake in a rope, there sutra, is really no snake to come in contact with my eyes.
Mental states like the feelings of pleasure and pain are directly cognised or perceived by us withut the help of any sense organ. All this shows that sense-object contact is not common to, and cannot, therefore be a defining character of, perceptions.
What, however, is really common to, and distinctive of, all perceptions is a feeling of ‘directness’ or ‘immediacy’ of the knowledge given by them.
We are said to perceive an object, if and when we know it directly, i.e., without taking the help of previous knowledge or any reasoning process (jnana-karanaka).
If at midday you turn your eyes overhead, you see the sun directly, and not by means of any process of inference or reasoning. There is neither any necessity nor any time for you to think and reason before the perception of the sun arises in your mind.
So some Indian logicians propose to define perception as immediate cognition (saksat pratiti), although they admit that perception is in almost all cases conditioned by sense-object contact.