Any definition of the mind is bound to be very limited and arbitrary. For example, modern psychology roughly divides the mind into three parts: the conscious, subconscious and unconscious. It is very easy to regard these definitions as fixed quantities or specific areas of the mind. Furthermore, one is inclined to gain the impression that the subconscious (below consciousness) and unconscious (beyond consciousness) regions of the mind are strictly and permanently inaccessible to conscious perception. This is a common belief but totally wrong. All regions of the mind are accessible to our awareness. That is, the so-called unconscious mind is only unconscious because of severe limitations in the freedom and scope of our awareness. Similarly, the subconscious mind is only below our conscious perception due to lack of awareness. If we develop our awareness, then the unconscious mind and the subconscious mind would no longer be unreachable and unperceivable. This is the case with someone who is self-realized; all the realms of the mind are within reach of his awareness. For him no part of the mind is truly unconscious or subconscious. This is important and applies to everyone; we are only unconscious of different parts of the mind because of restrictions and imprisonment of our awareness within a confined field.
We should be careful not to assume that any scientific, religious or philosophic division of the mind has any relationship with truth. It is merely an arbitrary division and classification. The mind is an indivisible whole. In a garden we might plant different areas with different vegetables and call them different plots; nevertheless this partition is only for convenience. These plots of land, no matter what vegetables they contain, are still an integral and inseparable part of the whole garden. Similarly, any classification of the realms of the mind is only a means to describe different aspects within the mind as a whole.
The purpose of this topic is to divide the mind into separate parts, but only as a means to describe how meditational practices relate to phenomena within the mind. In this way we hope to throw practical light on the nature of the mind and understand its relation with meditation.
It is generally assumed that the mind is that which is contained in the brain. This seems so obvious that few of us ever question its truth. Various great philosophers have said that the area or extent of the mind is either infinite or microscopic. Thus there are three possible theories of the mind: that the mind is atomic in size, brain-sized or macrocosmic in size. Let us consider these three speculations.