Further reading on Citta.
Awareness is the process of cittas experiencing objects. For a citta to arise it must have an object (aaramma.na). The object may be a color, sound, smell, taste, something tangible, or a mental object. These are the six external objects. Strictly speaking a mental object can be an internal phenomenon, such as a feeling, a thought, or an idea, but as forming the objective sphere of experience they are all classed as external. Corresponding to these external objects there are six internal sense faculties, called "doors" since they are the portals through which the objects enter the field of cognition. These are the eye, ear, nose, tongue, body and mind. Each of the five physical sense faculties can receive only its appropriate object; the mind door, however, can receive both its own proper mental objects as well as the objects of the five physical senses. When a door receives its object, there arises a corresponding state of consciousness, such as eye-consciousness, ear-consciousness, etc. The union of the object, the door or sense faculty, and the consciousness is called "contact" (phassa). There can be no awareness without contact. For contact to occur all three components must be present — object, door, and consciousness. If one is missing there will be no contact. The process of the arising of consciousness and the subsequent train of events is analyzed in detail in the Abhidhamma. A study of this analysis will show that only "bare phenomena" are taking place and that there is no "self" involved in this process. This is the no-self characteristic of existence.
The Arising of the Cittas
Cittas are classified in various ways. One such classification is according to their nature (jaati). In this classification we have:
Cittas which are resultant states of consciousness, vipaaka, the effects of previous kamma.
Cittas which are causes for action (kamma) through body, speech, or mind. We may call these "causative cittas." A wholesome citta (kusala citta) will issue in wholesome action and an unwholesome one (akusala citta) in unwholesome action.
Cittas which are neither kamma nor its result. These are called kiriya cittas. They are kammically ineffective, being merely functional. Some kiriya cittas perform simple functions in the process of consciousness, others represent the actions and thoughts of arahants, who no longer generate fresh kamma.
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