The development of insight, according to the suttas and commentaries, requires a high degree of samadhi (but not necessarily jhana): viewtopic.php?f=19&t=17107#p244480
“The words ‘insight alone’ are meant to exclude not virtue, etc., but serenity (i.e.
jhána), which is the opposite number in the pair, serenity and insight. This is for
emphasis. But the word ‘alone’ actually excludes only that concentration with distinction
[of jhána]; for concentration is classed as both access and absorption (see IV.32). Taking this stanza as the teaching for one whose vehicle is insight does not imply that there is no concentration; for no insight comes about without momentary concentration. And again, insight should be understood as the three contemplations of impermanence,
pain, and not-self; not contemplation of impermanence alone” (Vism-mhþ 9–10).
That "concentration is classed as access and absorption" is taken from the chapter of Concentration development, in other words, samatha bhavana. So i don't think we should take it to apply to sukkha vipassana- dry insight workers. In the suttas there are so many examples of householder, having obviously no previous jhanna nor access concentration as result of samatha bhavana (at least in that life), yet upon hearing the Buddha' exposition of the Dhamma, they attained enlightenment to different degrees.
Like RobertK, I am of the opinion that what "no insight comes about without momentary concentration" refers actually to right concentration, as ekkagata (the mental factor of concentration) arises with all citta. And they can be of different degrees, up to the level of jhanna when path consciousness occurs.
"In a person of right view, right resolve comes into being. In a person of right resolve, right speech. In a person of right speech, right action. In a person of right action, right livelihood. In a person of right livelihood, right effort. In a person of right effort, right mindfulness. In a person of right mindfulness, right concentration. In a person of right concentration, right knowledge
. In a person of right knowledge, right release.http://www.accesstoinsight.org/tipitaka ... .than.html
To me, the above actually supports the view that right concentration arises together with right view. As right view is of different degrees, from intellectual levels up to direct levels, the right concentration also is of different degrees. When the lokuttara citta arises, the 8 cetasikas arise all together at the same time, making right view, right concentration supermundane and thus right knowledge.
That being said, as it has been said many times, we do believe we are still at very low levels of understanding, so it s not to say " we just listen to the Dhamma then lokkutara citta will arise soon". It is indeed a long process. As Robert has pointed out, at the moment of insight where the mind door appears, at that moment, there's no other object appearing though only in a flash moment, it is a lone world at that moment. And the degree of concentration at that moment is very strong, and can be said to be of the degree of access concentration. So any little right understanding now, even intellectually, has right concentration accompanied which can be gradually buit up to the degree of access concentration when insight arises, and to aborption level when Nibbana is experienced.
I also noticed that very often, we mix up "understanding of the meaning of the words", and 'understanding intellectually". There can be listening many times with understanding of the meaning of the words, but there's no understanding intellectually. But if there is a moment of real understanding, even intellectually, it can be known that the quality of the mind at that moment is different, and it can become clearer and clearer. Thanks to what has been heard about the characteristics of the mental factors which arise with any wholesome citta, there can be a gradual investigation of the characteristics of the mental factors that arise at those moments (including sati, viriya, ekkagata, panna) for them to appear better and better as only elements. But only slowly and by conditions, totally.
Do you have any idea why "the four elements" are classified under samatha bhavana?