The Perfection of Wisdom - Mindfulness of death

The Buddha’s different methods of teaching Dhamma are in conformity with each other, there is no contradiction between them. For example, the Buddha taught mindfulness of death, marana sati. Moreover, he also taught that there are three kinds of death: momentary death (khanika marana), conventional death (sammutti marana) and final death (samuccheda marana). Momentary death is death at each moment, and this means that our life occurs during only one moment of citta. One may say that life lasts long, that a person is very old, but in reality, life is a series of cittas that arise and fall away in succession. If we reduce the duration of life that seems to be very long into just one extremely short moment of citta, we can understand that life occurs during only one moment of seeing. At this moment of seeing, there is just one moment of life that arises and sees; if there would not be seeing there would be no life. Seeing has arisen and sees, and then it dies, it lasts for an extremely short moment. At the moment we are hearing, life occurs only during one short moment of hearing and then there is death.
When someone who develops the perfection of panna is mindful of death, he should not merely think of death in conventional sense, sammutti marana. It is not enough to think, even with some degree of detachment, that there is nobody who can own anything, and that one day we shall be separated from all things, that all we used to take for self or mine will disappear. Merely intellectual understanding cannot lead to the eradication of defilements. The true understanding of momentary death, death occurring at each moment of citta, is different from understanding of death in the conventional sense. We should understand momentary death: each moment we are seeing, seeing arises and then dies. It is the same in the case of hearing, the other sense-cognitions and thinking. If we have right understanding of momentary death, we will be able to investigate and know as they are the characteristics of the realities that are appearing. This is mindfulness of death.
There are different levels of mindfulness of death, in accordance with a person’s understanding. There is mindfulness of death of the level of someone who develops calm and this is different from the level of someone who develops understanding by considering and investigating the characteristic of death which occurs each moment. If we are mindful of momentary death we come to see the disadvantage of clinging to what falls away immediately.