Before enlightenment can be attained, maha-kusala citta which is nana- sampayutta, accompanied by panna, has to consider and investigate the characteristics of all kinds of nama and rupa over and over again, life after life. In this way understanding of realities can grow. When panna has become keener and more accomplished, maha-kusala citta accompanied by panna that is vipassana nana (insight wisdom) can arise. The kind of panna that is vipassana nana can clearly realise the characteristics of nama and rupa through the mind-door, in accordance with the stages of insight that are successively reached. There are several stages of insight that have to be reached before enlightenment can be attained.