[419] Which phenomena (dhammā) are indeterminate (abyākata)?
On the occasion when one develops the path (magga) for rebirth in the formless (arūpūpapatti) and, having completely transcended the sphere of infinity of space (ākāsānañcāyatana), with the abandoning of pleasure and … enters and dwells in the fourth jhāna accompanied by the perception (saññā) of the sphere of infinity of consciousness (viññāṇañcāyatana) — on that occasion there is contact (phassa) … there is non-distraction (avikkhepa) … These phenomena are wholesome.
As the result (vipāka) of that same wholesome kamma of the formless sphere (arūpāvacara) having been done and accumulated, one, having completely transcended the sphere of infinity of space, with the abandoning of pleasure and … enters and dwells in the fourth jhāna accompanied by the perception of the sphere of infinity of consciousness; on that occasion there is contact … there is non-distraction … These phenomena are indeterminate.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.