traidhātuka (P. tedhātuka; T. khams gsum ཁམས་གསུམ་; C. sanjie 三界) is translated as "three realms," "three planes," "triple realm," etc. These are three realms within cyclic existence (samsara) in which beings take rebirth, according to Buddhist cosmology.
The three realms are:
- kāmadhātu ("sensory realm," "world of the five senses," "desire realm," etc.)
- rūpadhātu (form realm)
- arūpadhātu (formless realm)
Most types of sentient beings (sattva), including humans and animals, inhabit the desire realm. The form and formless realms are the domains of rare types of gods or heavenly beings.
Characteristics of the three realms
These three realms/planes have the following characteristics:
- the desire realm is principally dependent on external objects of sensual desire such as visual forms, sounds, smells, and so on;
- the form realm is principally dependent on the internal bliss of meditative absorption;
- the formless realm is principally dependent on being disenchanted even by the bliss of meditative absorption, on tranquility permeated by the feeling of equanimity alone.
Science and Philosophy in the Indian Buddhist Classics (Vol. 1) states:
- If these three realms are explained further by means of their body, feelings, and resources,
- the desire realm is characterized as follows: The body is coarse, experience is predominantly a mixture of pleasure and pain, and beings depend mainly on coarse food.
- The form realm is characterized thus: beings there have bodies in the nature of light, their experience is permeated mostly by feelings of bliss, and they do not rely on coarse food.
- The formless realm is characterized as follows: beings there do not possess a coarse physical body that symbolizes their nature as sentient beings, they abide with feelings of equanimity transcending feelings of pain and pleasure, and they do not depend on coarse food but live their entire life in meditative concentration focused solely on objects such as limitless space, which resemble the cessation of all mental engagement in other objects.
- It is stated that beings who live in the higher levels of the desire realm and beings who live in both the form realm and formless realm are celestial beings.
Alternate names for the three planes within traditional texts
Within traditional Buddhist texts, the three planes are referred to by the following names:
- traidhātuka (P. tedhātuka; T. khams gsum; C. sanjie; J. sangai; K. samgye 三界)
- traidhātu (T. khams gsum)
- trailokya (T. 'jig rten gsum; C. sanjie; J. sangai; K. samgye 三界)
- triloka (P. tiloka; T. 'jig rten gsum; C. sanjie)
- Buswell, Robert E.; Lopez, Donald S. (2014), The Princeton Dictionary of Buddhism, Princeton University
- Thupten Jinpa, ed. (2017), Science and Philosophy in the Indian Buddhist Classics, Volume 1: The Physical World, translated by Coghlan, Ian James, Wisdom Publications