[Updated as per the comments from Praveen.]
In routine life, we, as observers, are observing the observed.
Vedanta says that the Truth is that there is neither an observer, nor an observed. There is only observing. Patanjali, in his Yoga aphormisms, has described eight fold yoga. The last three steps are Dharana, Dhyana and Samadhi. Dharana is when the mind (the observer) is concentrating on one thing (the observed). However, the mind is still aware of several other objects apart from the one on which it is concentrating. Dhyana is an advanced stage of Dharana but the mind is still not still. Samprajnata Samadhi is when the mind (the observer) is fully concentrated on only one thing (the observed). In other words, this is also called Savikalpa Samadhi. The interesting thing about this samadhi is that there are still two entities here: observer and the observed.
However, Asamprajnata Samadhi is described as when the observer and the observed get dropped and only observing remains. This is also called Nirvikalpa Samadhi. This world of multiplicity that we see around ourselves is called relative reality (everything is in relation to another thing). And the absolute reality is considered only one and the reality is that everything is one.
This concept always bewildered me. I had analyzed the concept of everything being one (i.e. monism) from several angles and found it to be logically correct. However, whenever it came to the observer/observing/observed stuff, my mind just wouldn’t understand the logic. How can there be observing without an observer and an observed?
I have got a theory now. For past couple of days I have been thinking about it but haven’t found any flaw so far. I am yet to run it through a “knower of the knowledge” though.
A straight line is a connection between two points. This is one way of looking at the straight line. Another way would be that a straight line has two end points.
Let’s say that the two endpoints of the line are A and B while the line itself is L.
From the point of view of A, A exists, B exists and they are connected by L. While from the point of view of L, L alone exists. A and B exist as entities in relation to another. However, L exists on its own. A and B are the relative realities while L is the absolute reality of this relation.
A is the observer, B the observed and L observing. As per my understanding of Vedanta, A and B would be said to exist relative to each other and hence part of the relative reality. But the real nature of A as well as B is L which connects the two. And since both A and B are L only, in absolute terms, they are not two different entities.
When the observer thinks that it is one entity which is different from the observed (another entity), it is called ignorance or Avidya. When A thinks that there is only observing in the absolute terms, and hence A and B are not different, it is called right knowledge.
Hmmm. I think it makes sense.