The Natural Way of Development - Textbook knowledge and insight knowledge

Questioner: When I combine different methods I acquire more understanding of the three characteristics of impermanence, dukkha and anatta. They are explained in the textbooks I have read. I also have read about mindfulness of breathing and this helps me not to be distracted by other matters. If I have a  problem that I cannot solve I apply myself to mindfulness of breathing. But if I try to think, “seeing through the eyes is nama, it is non-self,” or, “hearing is non-self,”  I feel confused. There is still self all the time, self who is acting, who is thinking. I feel confused and worried about that.
Sujin: If you combine different ways of practice you are bound to become worried, because there is no panna which investigates and studies the characteristics of realities as they naturally appear. You said that the benefit derived from your way of practice is knowing the three general characteristics of realities: impermanence, dukkha and anatta. However, that is only textbook knowledge of the three characteristics. If you do not know nama and rupa as they appear, how can you know the three general characteristics of nama and rupa?  They must be characteristics of the nama and rupa that appear, one at a time.
It is through insight knowledge, vipassana nana, that the three general characteristics are penetrated. There cannot be vipassana nana if one does not know the different characteristics of the namas and rupas as they appear one at a time. If one does not know the difference between the characteristic of nama and the characteristic of rupa, the three general characteristics of realities cannot be penetrated.