This is a repost, that I jokingly posted as a rebuttal to one of the comments, which was, er, deleted. Here it is, where it should be, as a blog post:
(From The Discourse on the Dhammacakkappavatana Sutta, by Mahasi Sayadaw)
THE PATH OF RIGHT CONCENTRATION
"What, Bhikkhus, is Right Concentration? Here, in this teaching, the Bhikkhu, being detached from all desires (greed) and detached from other unwholesome things, enters into the first stage of absorption which is accompanied by thought conception (thinking), and discursive thinking (investigation), is filled with rapture (pitti) and happiness (sukha), born of detachment from evil thoughts." And so on, he enters into the four stages of jhāna. The Concentration involved in the four stages of jhāna is defined as the path of right concentration.
Here, Jhāna means not allowing the mind to wander about but having it fixed on a single object to remain tranquilized. According to Suttas, there are four types of Jhānas: (1) the five factors namely, vitakka, directing the mind towards an object or thinking of the meditation object: vicāra, repeated investigation on the object which has manifested; pīti, rapture or thrilling joy; sukha, happiness or pleasant feeling; ekaggatā, one-pointedness of calm mind, constitute the first jhāna. (2) After fading away of vitakka and vicārā, only three factors remain, pīti, sukha and ekaggatā to form the second jhāna. (3) Then without pīti, the two factors, sukha and ekaggatā constitutes the third jhānā. (4) In the fourth jhāna, sukha is replaced by upekkhā (equanimity) so that upekkhā and ekaggata form the two factors of the fourth jhāna.
These four types of jhānas may be higher Lokiya (mundane) jhānas also known as rūpavacara and arūpavacara jhānas or Lokuttarā (supramundane) jhāna accompanied by the noble path consciousness. The lokuttara jhāna samādhi is the path of noble right concentration proper; the lokiya jhāna samādhi may be classed as the path of right concentration if it forms the basis for the development of Vipassanā.
ASSERTION THAT VIPASSANĀ CANNOT DEVELOP WITHOUT JHĀNA
Hanging on to this statement of ours, some are saying that Vipassanā can be developed only after achieving purification of mind through attaining jhānic concentration. Without jhānic concentration, purification of mind cannot be brought about. Consequently vipassanā cannot be developed. This is a one-sided, dogmatic view. That access concentration in the neighborhood of jhāna, having the capacity to suppress the hindrances, can help attain the purification of view, leading thus to the development of vipassanā; that by so developing, attainment can be made up to the stage of Arahattaphala; that there are many who have achieved thus, are explicitly stated in the Visuddhi Magga etc. In the Sutta Pāḷi canons; for instance in the Mahā Satipaṭṭhāna sutta etc. there is very clear teaching that Arahattaphala may be achieved by contemplation of such objects as body postures etc. which can cause only access concentration to come about. The Anussatithāna sutta of the Aṅguttara Pāḷi canon states that the samādhi which develops out of recollections of virtues of the Blessed One etc. is adequate enough to be used as a basic concentration for the development of higher knowledge up to the state of Arahatship. The commentaries which expound on the section on clear comprehension also definitely affirm that pīti can be aroused by recollecting just on the virtues of the Blessed One and the Sangha; and that the pīti so aroused can be meditated upon as being perishable as being impermanent resulting subsequently in attainment of Arahattaphala.
These authorities state further that the innumerable people by lakhs, millions and crores who became liberated during the course of discourses given by the Buddha were not all skilled in jhānas. It is most probable that many of them were unequipped with jhāna attainments. But they must have achieved purification of mind because their mind then was described as responsive, tender, free from hindrances, exultant and pure. Commentaries clearly mention that it was at such opportune moment that the Blessed One delivered the most exalted, sublime discourse on the four truths which only the Buddha alone could expound. Commentaries clearly state that his audience attained higher knowledge as a consequence of listening to such deliverances.
In view of such consideration, definitions given in the teachings of the right concentration in terms of the four jhānas should be regarded as a superlative method of description; the access concentration, although described as an inferior way, may also be taken as the right concentration which can accomplish the purification of mind. The said access concentration has the same characteristics of suppressing the hindrances as the first jhāna. They are similar too in having the same five factors of jhāna, namely, vitakka, vicāra, pīti, sukha and ekaggatā. Consequently we take it that the Blessed One had included both the proper access concentration and the nominal access concentration under the category of the first jhāna as an inferior way of definition.
Jhāna means closely observing an object with fired attention. Concentrated attention given to a selected object of meditation such as respiration for tranquility concentration gives rise to samatha jhāna, whereas noting the characteristic nature of rūpa, nāma and contemplating on their impermanence, unsatisfactoriness and insubstantiality brings about vipassanā jhāna.
We have given the following summarised note for easy memory:
1. Close observation with fixed attention is called jhāna.
2. There are two types of jhāna — samatha jhāna and vipassanā jhāna.
3. Fixed attention to develop only tranquility is called samatha jhāna.
4. Contemplating on the three characteristics constitute vipassanā jhāna.
5. There are three kinds of samādhi (concentrations); Momentary, Access and Absorption or fixed concentrations.
The momentary concentration mentioned above refers to the fairly calm state before access concentration is attained in the course of meditating upon tranquility meditation objects (samatha kammaṭṭhāna objects) and also to the vipassanā Samādhi. And of these two, the vipassanā samādhi
having the same characteristic of suppressing the hindrances as access concentration is also called access concentration as explained above. That this vipassanā, momentary concentration, when it becomes strongly developed, can keep the mind well tranquilized just like the absorption concentration, has been clearly borne out by the personal experiences of the yogīs practising the Satipatthāna meditation.
Therefore in the Mahā Tikā, the sub-commentary to the Visuddhi Magga, we find: “True, khaṇika cittekaggatsā is (vidassanā) samādhi which lasts for only the duration of the moment of each arising. When this Vipassanā khaṇika samādhi occurs uninterruptedly with nāma. rūpa as its meditative objects maintaining tranquility in a single mode, at a stretch and not being overcome by opposing defilements, it fixes the mind immovably as if in absorption jhāna.
Accordingly a person engaged in vipassanā meditation and intent on developing himself up to the path and fruition stage, should endeavour, if possible to reach the first jhāna or the second, the third, the fourth jhāna or all the four jhānas. And having any of them, should train himself to maintain them and to be skillful with them. Failing, however, to reach the jhānic stage, he should strive to bring about the access concentration in the neighborhood of the jhāna.
The vipassanā yānika, on the other hand, who begins with the contemplation on nāma, rūpa such as the four primaries, should try to become established in vipassanā khaṇika samādhi which is capable of suppressing the hindrances just like the access concentration. When fully established thus, the series of insight knowledge will arise beginning with the analytical knowledge concerning nāma and rūpa (nāmarūpa pariccheda ñāṇa). Thus vipassanā khaniks samādhi and access concentration are also to be regarded as the path of right concentration.