Concepts I - Six objects

There are objects that are real and objects that are not real. Objects can be experienced through the six doors and they can be classified as sixfold:

Visible object (ruparammanùa) can be known through the eye-door.

Sound (saddarammana) can be known through the ear-door.

Odour can be known through the nose-door.

Flavour can be known through the tongue-door.

Tangible object can be known through the body-door.

Dhammarammana (mental object) can be known through the mind-door.
As to visible object, this is the reality that appears through the eyes. It is the object of víthi-cittas that arise depending on the eyesense, the cakkhuppasada-rupa. When visible object has fallen away there are many bhavanga-cittas arising and falling away, and then víthi-cittas of the mind-door process experience the visible object which has just fallen away. Thus, visible object can be experienced through two doors: through the eye-door and, after there have been bhavanga- cittas in between, through the mind-door.
As to sound, this is the reality that appears through ears. It is the object of víthi- cittas that arise depending on the earsense, the sotappasada-rupa. It appears through the mind-door after there have been bhavanga-cittas in between. There have to be bhavanga-cittas after each process of cittas. Thus, there must always be bhavanga-cittas in between a sense-door process and a mind-door process. When we hear sound and know the meaning of what is heard, these are different processes. When one knows the meaning of a word there are mind-door processes of cittas that think of that word. These cittas are different from cittas of the ear-door process that experience the sound that has not yet fallen away.
As regards odour, this is the reality that appears through the nose. It is the object of cittas that arise depending on the rupa that is smelling-sense. After there have been bhavanga-cittas in between, there are cittas of the mind-door process which experience odour.
As to flavour, this is the reality that appears through the tongue. It is the object of cittas that depend on the rupa that is tasting-sense. After there have been bhavanga-cittas in between there are cittas of the mind-door process which experience flavour.
Tangible objects are cold, heat, softness, hardness, motion and pressure that appear through the body-sense. They are the objects of cittas that arise depending on the bodysense. After there have been bhavanga-cittas in between, there are cittas of the mind-door process which experience tangible object.
The five classes of sense objects, which have just been mentioned, can appear through the six doors. When the cittas of the eye-door process have arisen and experienced visible object through the eye-door there are, after there have been bhavanga-cittas in between, cittas of the mind-door process which experience visible object through the mind-door. It is the same with the experience of the other sense objects. These objects are experienced by the cittas of the corresponding sense-door processes, and then, after there have been bhavanga-cittas, they are experienced through the mind-door. Thus, each of the five classes of sense objects is experienced through its corresponding sense-door and through the mind-door. They are experienced through the six doors: the eye-door, the ear- door, the nose-door, the tongue-door, the body-door and the mind-door.
There is one other class of objects, namely dhammarammana (mental objects). This class of objects can only be experienced through the mind-door. There are six kinds of dhammarammana:

The five pasada-rupas (senses),

Sixteen subtle rupas (sukhuma rupas),

Citta, cetasika, nibbana and concepts (pannattis).
Five classes of dhammarammana, namely, the pasadarupas, the subtle rupas, citta, cetasika, and nibbana are paramattha dhammas. One class, the pannattis, is not paramattha dhamma.