A person sitting by a first floor window watching the people walking and traffic on the road. This persons eyes see, ears listen, nose can smell if any, in a chair arms and legs at rest and whole body at rest. In his mind nothing is happenning as stated in some of the reply's like color identification or sound recogination or smell sense, like the TV is ON but no one is watching it. Then this person suddenly realises that even though the sensory process is going on as if machnical there are no new process(thoughts). The mind will always function in a machenical capacity even when it is not generating thoughts. Some naturally fall into such states even without knowing it and some train via meditation and either way the feeling is same but explaining that feeling is difficult because each person's feeling will be unique to them only.
I'm replying 5 years after the post, forgive me but i joined just now and thought this was an interesting discussion.