"But," asked Vaccha persistently, "when one who has this emancipation of mind (freed from self) dies, where does he go, where is he reborn?
The Buddha replied:
"The word 'reborn' does not fit the case."
"Then he is not reborn?"
The things to watch are comparative judgments, thoughts and worries. I don't think you need to watch any in the physical world of form. I'm looking at a computer right now but it's basically empty until I employ the keyboard. Observing doesn't effect any object. If you watch from within the activity of the mind does the work of Buddha.