Three Realms of Existence

In Buddhist cosmology, saṃsāra, or cyclic existence, contains three realms. The Buddhist classification differs from earlier Indian cosmology, which described the three spheres of heaven, earth, and hell (or underworld). According to the Buddha’s presentation, these realms are not external states but rather mental projections. These three states/realms are:

1. The desire realm (Skt. kāmadhātu; Tibetan འདོད་ཁམས་, dö kham).
2. The form realm (Skt. rūpadhātu; Tib. གཟུགས་ཁམས་, zuk kham).
3. The formless realm (Skt. arūpadhātu; Tib. གཟུགས་མེད་ཁམས་, zuk mé kham).

In The Application of Mindfulness of the Sacred Dharma[2], found within the Hinayana section of the Tibetan Dege Kangyur,¹Introduction, The Noble Application of Mindfulness of the Sacred Dharma, Ārya­saddharma­smṛtyupasthāna, I, note 4: “This placement among the Hīnayāna sūtras has been a topic of some debate among Tibetans, since one finds frequent occurrences of the term “Mahāyāna” within the sūtra’s later sections.” Buddha Sakyamuni taught that sentient beings take rebirth in these three realms based on their karma. The Buddha said:

Birth in the three realms
Is appropriated by three types of mind and the product of three flaws
That thus ripen in three places.
As causes and conditions come together,
Distinct karmic formations appear.
The ripening of karmic actions
Appears as the three realms.

Transformations occur
In accordance with the character of the mind.
Thus, virtue engenders virtue
And evil begets evil.
Karmic action is associated with the mind
And the result with the karmic action.
Thus instigated by the mind and karmic action,
This is known as cyclic existence.

The Noble Application of Mindfulness of the Sacred Dharma

Desire Realm

The desire realm takes its name from the fact that sentient beings living here are subject to strong emotions and have strong desires and cravings for sense pleasures. There are six classes of sentient beings in the desire realm as follows:

1. Hell beings
2. Pretas (starving spirits)
3. Animals
4. Humans
5. Asuras (demigods)
6. Desire realm gods

Within the desire realm, there are six separate states of existence known as celestial paradises or heavens that are inhabited by gods. Those who are reborn here enjoy long life spans in very pleasureable conditions. Although traditional Indian cosmology refers to them as gods or deities, they are not creator gods.

Form and Formless Realms

Sentient beings who inhabit the form and formless (or immaterial) realms are also usually referred to as gods. Sentient beings take rebirth in one of these heavens based upon the virtuous karma that they accumulated through the practice of one of the four causal meditative states, or dhyānas. These dhyānas should be understood as states of existence rather than as places, even though they are described as realms. 

The form realm contains 17 separate heavenly states of existence, and sentient beings take rebirth depending upon their mastery of particular dhyānas. 

The formless realm comprises four realms and is inhabited by gods without bodily form, who rest in four states of absorption. It is said that because they do not possess form, they are unable to hear the Dharma. One attains rebirth there by passing away while in the meditative absorption of one of the four formless states

In The Application of Mindfulness of the Sacred Dharma sutra, the Buddha repeatedly drew attention to the fact that the mind creates the experience. This applies equally to the highest and lowest forms of existence. In the fourth chapter of this sutra, it states:

Gods, asuras, piśācas, nāgas,
Mahoragas, and rākṣasas
All have a single lord, the mind.
This is the king of the three realms of existence.

Mind leads to heaven
And to the realm of humans.
Mind also leads to the lower realms,
Making people roam aimlessly.

The mind that is confused and impaired
By all its useless objects
Is driven by craving,
And confined to infinite pain.

The Noble Application of Mindfulness of the Sacred Dharma