Try this exercise:
Close your eyes....
Watch thoughts come and go....
Where do thoughts arise from? Where do thoughts go to?
Can you stop a thought that has arisen?
Can you choose to only think thoughts of a blue flower?
Can you choose to NOT think about a pink elephant?
and finally, here & now,
Can you think a thought?
Are you the thinker of thoughts?
Are they YOUR thoughts?
Are they YOUR thoughts?
One of the bindings of the illusion of the separate self, is the belief in the thinker, and the thinker being "I" or "me". There is identification with the voice in the head. This may vary to different degrees in different people, yet this identification is common nonetheless and is something that is essential to address when Awakening to no-self is undertaken.
When we refer to simple experience (refer to my article on Direct Experience (d.E.)), we see that thoughts arise from nowhere, and then disappear back in to nowhere. Thoughts may manifest as a voice heard, or an image, but they are empty of any inherent substance.
When we try to stop a thought, it is observed that we cannot. Some may claim that they are able to stop a thought once it has arisen, but if looked at carefully, there is just a sensation (squinting of eyes, tightening of face muscles), and a thought. Simply, you cannot stop a thought, because there is no you to do any such thing. The experience observed is simply the experience observed and may cause the assumption that a thought can be stopped, yet it can never be stopped. Thoughts will continue to arise.
When we try to only think a thought of a blue flower, that thought of a blue flower may be held for very long periods of time that may give rise to an assumption that it is possible, yet, it is never possible to ONLY think of that blue flower. Other thoughts will continue to arise, all on their own.
When we try not to think about a pink elephant, the thought of a pink elephant will still eventually arise. Although one may assume that when the face muscles are tightened and the eyes are squinted (an attempt that is assumed to be thought control) that the thought will be prevented from arising, it inevitably arises at some point and in some form. It may seem possible to not think about a pink elephant for a while, yet, the pink elephant thought will arise, nonetheless.
If I ask you, can you think a thought? The immediate answer will probably be "yes I can think a thought". Notice how that is just a thought?
Then a thought may say " I am going to think of a BLUE FROG" and voilà another thought "BLUE FROG" and then another thought "I just thought of a BLUE FROG" and a further concluding thought "I am the thinker of thoughts and I just thought a thought". Notice how these are all just thoughts? Can thoughts think? Is perhaps "You" another thought?
And finally... are You the thinker of thoughts? If you are... then where is that thinker? Where is the You? When looked for in Experience, it can never be found, because there is no such thing, no such thinker, no such You! There is always only ever a thought saying "Yes I am the thinker". Thought are always self-referencing, and they always center around an "I" or "me". There is never a thinker of thoughts, and all one has to do is refer to Experience, here & now, to see that.