I had a discussion on dhammawheel on this topic and add some of the post from that:
Q: Mundane jhana is your term so I’m not sure what exactly what you mean.*
However, in the suttas, right samadhi is usually defined as the four jhanas (e.g. SN45.8) and the four jhanas are defined in many suttas, such as DN2.
is it like these?:
MN 8 Sallekha sutta 4. "It is possible here, Cunda, that quite secluded from sensual pleasures, secluded from unwholesome states, some bhikkhu enters upon and abides in the first jhana, which is accompanied by applied and sustained thought, with rapture and pleasure born of seclusion. He might think thus: ‘I am abiding in effacement.’ But it is not these attainments that are called ‘effacement’ in the Noble One’s Discipline: these are called ‘pleasant abidings here and now’ [41] in the Noble One’s Discipline. [..]
It is possible here that with the abandoning of pleasure and pain, and with the previous disappearance of joy and grief, some bhikkhu enters upon and abides in the fourth jhana, which has neither-pain-nor-pleasure and purity of mindfulness due to equanimity. He might think thus: ‘I am abiding in effacement.’ But it is not these attainments that are called 'effacement’ in the Noble One’s Discipline: these are called 'pleasant abidings here and now’ in the Noble One’s Discipline.
That is what I mean by mundane jhana.
Many could attain such jhanas during and even before the Buddha - it was a different time from now - but those adepts still had to learn Dhamma and develop satipatthana and see that these are merely compounded elements.
Thus seeing into conditionality is the essence and we see in the texts even those who never developed mundane jhana if they were wise enough they could understand and penetrate into anicca, dukkha and anatta, the path of the dry insight worker. These ones studied the nature of reality in the present moment - even while walking, talking or urinating. This present moment insight of the vipassana yanika still comes with samadhi but not mundane jhana - it is momentary.
At the brief moment of attainment even for the vipassana yanaika this samadhi is so strong that it is given the name jhana - a different one from mundane jhana. For more on these different jhanas see: https://classicaltheravada.org/t/two-ty … jhana/2092