Absorption in Insight Meditation
Insight meditation and absorption have some characteristics in common. When the practice of mindfulness is well established at the exploratory stage, i.e. knowledge by comprehension (sammasanañāna), there are initial application (vitakka), sustained application (vicāra), joy (pīti), bliss (sukha), and one-pointedness (ekagattā). Thus, whenever the meditator observes any phenomenon, his insight meditation is somewhat like the first absorption with its five characteristics.
When the meditator gains insight-knowledge of the arising and passing away of all phenomena, he is fully aware of an arising object without initial or sustained application. He has intense joy, bliss, and tranquillity, thus his meditation is somewhat like the second absorption with its three attributes.
The disappearance of the light, and so forth — the corruptions of insight (upakkilesa) — marks an advance in the insight-knowledge of the arising and passing away of phenomena. Then there is no joy, but bliss is very intense. The mind is tranquil and free from distractions. The meditator has the bliss and one-pointedness that are characteristics of the third absorption.
The higher levels of insight-knowledge such as knowledge of dissolution (bhangañāna), wherein the meditator sees only the passing away usually have nothing to do with joy. They are characterised by equanimity and one-pointedness. The former is especially pronounced at the stage of knowledge of equanimity about formations. At this stage the insight meditation is akin to the fourth absorption with its two attributes of equanimity and one-pointedness.
Furthermore, at times the meditator’s whole body disappears, giving him the impression of being in space. At that moment he is like a person absorbed in ākāsānañcāyatana jhāna. At other times, attention is fixed exclusively on consciousness and then the meditator’s state of consciousness resembles viññānañcāyatana jhāna. On occasions, it seems as though he were noting nothingness, a state somewhat like ākiñcaññāyatana jhāna. Sometimes the consciousness may be so transcendental that it becomes non-existent, a state on par with that of nevasaññā-nāsaññāyatana jhāna.
These characteristics that insight meditation has in common with absorption often leads to complacency, which is an obstacle to spiritual progress. In meditation it is necessary to note these unusual experiences and reject them. In the Sallekha Sutta, the Buddha, after pointing out the misleading nature of absorption, proceeds to spell out the practice of effacement that is calculated to root out defilements.
I also wonder if one could use the pleasant feelings of varying intensity ranging from occasional to pervasive which arise of insight meditation to enter the first absorbtion?