What separates a sentence from previous or next sentence in a written document? Yes, periods, question marks, exclamation marks, interrobangs etc. In case of speech, you find that there are certain pauses after sentences and usually if a speech is documented and later on read by someone, there is a certain mapping between pauses in the speech and pauses in the reading.
What is a thought? Does it exist in isolation?
These were the questions which occurred to me when I started practicing meditation. In meditation, all I had to do was to witness my thoughts and feelings. I had to try to be aware of arising and subsiding of each and every thought. That seems to be an easy task doesn't it? Though meditation is all about slowing down your thought process by making yourself more aware of them; there exists nothing called ‘a singular thought’. What exists, in my very humble opinion is ‘Stream of thoughts’. There might be gaps in this seemingly incessant streaming of the thoughts because of meditation or unconsciousness, but there never exists a singular thought, in isolation with the stream. In other words, as U G Krishnamurthy had put it once “You will find everything about thought, but you will never find thought.”
What are the boundaries of thought? Where does a thought start and where does it end? Are there any boundaries of thoughts?
Suppose I witnessed following chunk in my thought stream during my meditation practice:
[ I am simplifying a very complex process involving visual-spatial, auditory-sequential, muscular sensations and other factors into a mere verbal representation, in order to help easily analyse it]
Zelvin is a good boy. Cat is Fat. I went to market but Bob is not my uncle. Johnny is never in the place and there is doomsday around the corner.
Can we tell what a thought is, in the chunk above?
No. We cannot.
A sentence is known because of delimiters but there are no delimiters for thoughts in my experience. We don't always think in words. We think in images as well but conscious witnessing creates an agent which incessantly keeps translating sensory impulses and other types of thoughts into words. Now if for analysis we consider that thoughts occur to us only in words. The witnessing agent is ever ready with thoughts. This means that even if there exist certain gaps in your mind streams, they don't act as delimiters for two consecutive thoughts (but wait, I said there are no singular thoughts, therefore the idea that there could ever be two separate thoughts in our mind stream is not valid.) When we think in words, there is no singular thought because there exist no gaps and there are streams of thoughts. What actually exists is streaming of thoughts in chunks and occasional gaps in it.
What then is slowing down of thoughts? It's the decrease in the rate of mind's toggling from one sense object to another. Or it’s the decrease in the rate of switching of mind from one field of thought to another. One field of thought is on or multiple streams of thought where most of the thoughts are related to each other and connect well as to create meaning and coherency.