Sitting in dhyana (meditation), first thoughts of the past or future most commonly will arise. Thoughts about "self" as object or other objects of thought might arise. With practice gross thoughts are replaced by subtle thoughts. Then the mind wanders less onto objects of thought and increasingly into that most subtle and rarified/empty space of pure consciousness (swarupa-sunyam) as even beyond any ned to designate words, concepts, or form. With practice there are no longer any more mental objects that arise, no image of a separate self as observer, no need or dependence upon changing anything or even meditating.