The Stages of Vipassana - 3rd stage of vipassana nana - 1

The third vipassana nana is comprehension by groups (sammasana nana). This is the panna that clearly realises the rapid succession of namas and rupas as they arise and fall away. When this stage of insight has not yet arisen, one knows that nama and rupa arise and fall away very rapidly, but the rapid succession of namas and rupas as they arise and fall away does not appear. At the first stage and at the second stage of insight, panna penetrates the characteristics of nama and of rupa, one at a time, as distinct from each other, but it does not yet realise their rapid succession as they arise and fall away.
The first, the second and the third stages of insight are only beginning stages, they are called 'tender insight" (taruna vipassana). They are not “insight as power” (balava vipassana), that is, insight which has become more powerful at the higher stages. At the stages of tender insight, there is still thinking of the namas and rupas that are realised. However, although there is thinking, different dhammas are not joined together into a whole, into “the whole world,” such as one used to do.
Since there is still thinking of the nama and rupa at the three beginning stages of vipassana, panna is called "cinta nana", cinta meaning 'thinking' or 'consideration'. Some people may have misunderstandings about the stages of insight where there is still thinking. They may believe that there is already “tender insight” when one considers and notices characteristics of nama and rupa and has more understanding of them. However, so long as vipassana nana has not arisen yet one cannot penetrate the nature of anatta of vipassana nana. One cannot understand that vipassana nana, which clearly realises the characteristics of nama and rupa through the mind-door, can arise at any place and can take as object whatever reality appears. It arises because of its own conditions and it cannot be directed or controlled.
Someone may erroneously believe, when he is aware, considering and noticing the characteristics of nama and rupa, that he has clear understanding of them and that he has already reached the first stage of insight, knowledge of the difference between nama and rupa (nama- rupapariccheda-nana). A person can have such misunderstanding because he does not yet know that vipassana nana must appear as anatta  (as not self), just as the other types of nama that appear. When vipassana nana arises, characteristics of nama and rupa appear through the mind- door. The rupas that are sense-objects are experienced through the corresponding sense-doors and after each sense-door process the object is experienced through the mind-door. However, when there is no vipassana nana the mind-door process does not appear; it is as it were, hidden by the sense objects experienced in the sense-door processes. At the moments of vipassana nana, rupas appear very clearly through the minddoor, and at that moment the mind-door hides, as it were, the sense-doors. Then the situation is opposite to the moments when there is no vipassana nana.