If the aspirant (Yogavacara) who is doing the practice knows that his Citta has become free, ana if at that time he has Reviewing Knowledge (Paccavekkhana Nan& #3642;a), his Citta does not expand.1 The reason for this is given under the heading of Stage 4, which says that we must have mindfulness to watch and be the master of the sense doors.
When objects arise and die away within the fields of the senses, one must be aware of them. If one is then aware of them, one has Understanding (Vijja). If one is not aware of them, one has Ignorance (Avijja). In this, the eye door is not important, for the eye is like a telescope, and it is the man who looks through the telescope that matters, and not the instrument itself. Similarly, the ear is like a radio receiver, and it is the man who hears that matters, and not the radio set. In the same way, the man who smells odours, savours, and who feels contacts, is the one who matters, and not the instruments of these senses.
One should therefore only be concerned with that which is of importance; being that which accepts the mental objects which are received by the mind.2
The mind is chief.3 The mind is to be found within the Mind Door. When an object comes within the sphere of one of the external sense doors, the sensation is very rapidly conveyed to the mind where it becomes known; this is like messages which are conveyed along telephone wires. Because of this, one should not watch the other sense dooars, which would only make difficulties, but watch the mind door alone, which is quite sufficient.
When the person who is doing the practice uses mindfulness to guard the doors, then he must do so by watching the mind door only. When objects come within the field of the senses and the ensuing sensations give rise to knowledge, he must not look anywhere other than the mind door for it would only lead him into confusion.
This is like someone who goes to the cinema. While he is there, he watches the screen, for this is where the images and actions are to be seen. Before the images are projected, the screen is blank or empty. As soon as the projector is operated, the images appear on the screen; but the projector will only operate if the projectionist is present. When the images are clearly seen, then the screen is no longer apparent and one sees in it’s place, houses, cities, rivers and streams, animals and men, the hero or heroine of the story and countless other things.
Generally speaking, there are only two ways of looking; the first is that of someone who watches the story with pleasure; and the second is that of merely looking at the screen. In other words, looking at the heart base. These are the only two ways.
When no object is present, the heart base remains blank or empty, but as soon as the Impact of Sensation (Sankhara) gather and flavour the sensations, and is the sphere of the heart base. One will see formations, some of which are past, some present and some future, and within the three realms of conscionsness; these being, the sensual, form, and form less realms, all of which are to be found in the heart base.