When any thought arises, say that I want money. The first thing that we understand that, I want money. So if we analyze this further. This thought arises in my mind and then it proceeds to our intellect, Consciousness and finally ego to act on the same.

If, we go in the reverse order.  We can understand the Ego is acting based on the input from consciousness and it from the intellect and finally intellect is influenced by Mind where the thoughts are created.

Hence the source of all thoughts is our mind; it is here where we get information from the sensory organs to the mind and this mind creates thoughts. Mind and thoughts are the same as mind exists only for the sole purpose of creating thoughts.

Then further when we try to understand why are these thoughts created, we realize that these thoughts are created for me. Meaning the mind thinks “I need money”.

Who is this “I”, that the mind is thinking about? Mind usually associates its thoughts to the physical body and hence it thinks that “I - refers to the physical body”. But when the mind is made thoughtless or when we do not create thoughts in our mind then for the mind this body will not exist, but even at that time there is awareness in us. What is this awareness? This awareness is beyond the body as there are no thoughts, since thoughts are created when we interact with the external world. Further in this situation when the mind quiet and if it questions “Who am I”, then mind cannot associate ‘I’ to the physical body or even the mind (as it is quieted), as mind itself does not exist as there are no thoughts. Then who is this ‘I’? When mind is transcended by this way, then what is left? After this stage only awareness exists in our mind. What is this awareness and how does this feel? Will be the question at this point; is this the Brahman that we talk about?

How can I say this as I have not reached this stage of thoughtlessness; to achieve this stage meditation and protecting the mind is a very important requirement; During meditation mind can be made thoughtless, and once thoughtless we become aware of the emptiness due to the lack of thoughts.