It should be first made clear that, in Buddhist psychology, “feeling” (Pali: vedana) is the bare sensation noted as pleasant, unpleasant (painful) and neutral (indifferent). Hence, it should not be confused with emotion which, though arising from the basic feeling, adds to it likes or dislikes of varying intensity, as well as other thought processes.
Feeling, in that sense, is one of the five Aggregates or Groups of Existence (khandha),constituting what is conventionally called “a person.” The specific factors operative inemotion belong to the Aggregate of Mental Formations (sankhara-kkhandha). Feeling is one of the four mental Aggregates which arise, inseparably, in all states of consciousness; the other three are perception, mental formations, and consciousness.
Feeling arises whenever there is the meeting of three factors, i.e., sense-organ, object and consciousness. It is called the meeting of these three that, in Buddhist psychology, is called sense-impression (contact, impact; phassa), which is a mental, and not a physical process. It is sixfold, as being conditioned either by of the five physical senses or by mind. it is this sixfold sense-impression by which the corresponding six feelings are conditioned. In the formula of the Dependent Origination (paticca-samuppada), this is expressed by the link: “Sense-impression conditions Feeling” (phassa-paccaya vedana). When emotions follow, they do so in accordance with the next link of Dependent Origination: “Feeling conditions Craving” (vedana-paccaya tanha).
The feeling that arises from contact with visual forms, sounds, odors, and tastes is always a neutral feeling. Pleasant or unpleasant feelings do not always follow in relation to these four sense perceptions; but when they follow, they are then an additional stage of the perceptual process, subsequent to the neutral feeling which is the first response.
But bodily impressions (touch, pressure, etc.) can cause either pleasant or unpleasant feelings.
Mental impressions can cause gladness, sadness or neutral (indifferent) feeling.
Feeling is one of those mental factors (cetasika) which are common to all types of consciousness. In other words, every conscious experience has a feeling tone, even if only that of a neutral or indifferent feeling, which also has a distinct quality of its own.
Feeling by itself (if one could so separate it) is, as it was already said, the bare sensation noted as pleasant, painful or neutral. The subsequent emotional, practical, moral or spiritual values attached to that basic feeling are determined by other mental factors that subsequently arise in relation to that feeling, but, by way of classification, belong to the Aggregate of Mental Formations (sankhara-kkhandha). It is the quality of those other mental functions that makes the co-nascent feeling, too, to be either good or bad, noble or low, kammic or non-kammic, mundane or supramundane.
Feeling may stop at the stage of bare sensation in all weak states of consciousness, but also when there is mindful control of feelings. In such cases, there is no evaluation of these feelings, emotionally or intellectually.