Why Doesn’t the Buddha Preach the Dharma in the Formless Realm?

Formless realm devas possess no physical body yet retain consciousness; where there is consciousness, there exists the aggregate of consciousness. Although they have consciousness, they remain in meditative absorption, unable to hear the Dharma, let alone contemplate it. Lacking a body does not make them human, yet they are beings of the heavenly realm, a higher form of life. Sensation, perception, and mental formations—the five universal mental factors—are all present across the eight consciousnesses. Formless realm devas possess the sensation, perception, and mental formations of consciousness, those of the mental faculty (manas), and also those of the eighth consciousness (ālaya-vijñāna).

The Buddha can preach the Dharma to devas in the formless realm, but devas in the form realm cannot hear it, humans in the human realm cannot hear it, and spirits and ghosts cannot hear it. Formless realm devas are so few, all being non-Buddhists, constantly absorbed in meditation; thus, there is simply no need to preach the Dharma to them. From another perspective, beings in the second dhyāna cannot hear the Dharma, much less in meditative states beyond the fourth dhyāna, where hearing and contemplating the Dharma become impossible. Therefore, the Buddha does not go to the formless realm to preach the Dharma. The Buddha delivered the Avataṃsaka Sūtra and the Kṣitigarbha Sūtra in the desire realm heavens and form realm heavens, which were later transmitted to the human realm. Other sūtras were preached in the human realm, enabling devas to descend and hear the Dharma, while spirits, ghosts, and animals can also listen. This way, a greater number of sentient beings are liberated.