The Profound Meaning of Vijñapti-mātratā in the Diamond Sutra (22)

The Desire Realm encompasses six heavens, human beings, and beings of the three evil paths. The Form Realm comprises eighteen heavens, with thirteen heavens from the First Dhyāna to the Fourth Dhyāna, and five Pure Abodes, including the Heaven Free from Afflictions, the Heaven Free from Heat, the Heaven of Beautiful Appearances, the Heaven of Beautiful Manifestations, and the Heaven of No-Thought. Third-fruit Arhats cultivate here, severing their final afflictions, ego-conceit, and attachment to the three realms before attaining the fourth fruit of Arhatship. They may then enter nirvana without residue or turn their minds toward the Mahayana, taking rebirth to learn the Bodhisattva path. Other beings cultivate in the Five Pure Abodes; upon becoming weary of the form body, they abandon it and ascend to the Formless Realm. The Form Realm entails the burden of form, while "formless" refers to the Formless Realm's lack of a physical body. In this realm, beings possess only the conscious mind, manas, and ālaya-vijñāna, with the mind abiding motionless in concentration.

The Formless Realm consists of four heavens: the Heaven of Infinite Space, the Heaven of Infinite Consciousness, the Heaven of Nothingness, and the Heaven of Neither Perception Nor Non-Perception. Beings in the Formless Realm also cultivate emptiness meditation, aiming to enter nirvana without residue. However, failing to fully comprehend the principle of emptiness, they remain within the cycle of the six paths. This is exemplified by the Buddha’s heterodox teacher, Uddaka Rāmaputta, who attained the highest dhyāna, the concentration of neither perception nor non-perception. Mistaking this state—where thought is absent—for nirvana, he did not realize that an extremely subtle thought still persisted within that concentration. As long as deluded thoughts exist, one cannot transcend the three realms or attain liberation. After attaining enlightenment, the Buddha wished to liberate his teacher. Using his divine eye, he saw that Uddaka had been reborn in the Heaven of Neither Perception Nor Non-Perception and would not emerge from that concentration. The Buddha lamented that upon descending from that heaven, his teacher would fall into the three evil paths and suffer.