Buddhist Cosmology: The 31 Realms of being
Some people think that as Buddhists believe in rebirth, there is no heaven. Actually no, Buddhism has more hells and heavens than most other religions. There are 31 realms or states of being described in early Buddhism - there are probably more than this, given each state has sub levels but this is a starting point. At a more general level, Buddhism admits that there may be other planets or worlds out there including the possibility of more than one world with humans and any of the above mentioned realms.
The thirty one realms naturally call for a lot of imagination - even if they are seen as too fantastic to take seriously, they can be viewed as states of mind that we could experience though the more skillful ones are very difficult to access. In another context, the levels also represent types of consciousness, some of which can only be accessed by meditation. Finally, Buddhists don't actually believe in these realms given that the Buddha said not to take scriptures too seriously; these realms represent states that are possibilities that may inspire faith and confidence in the power of actions and their consequences. You can actually undertake voyages of explorations into these worlds by looking around or journeying using meditation as a tool.
Gods or Devas frequently occur in Buddhist texts. They represent beings who have been born in a fortunate or celestial realm of being and are described as radiant with very long lives. The Buddha was visited upon by gods interested in his advice or comments and the Buddha was known as the teacher of gods and men. There was no concept of a supreme God in ancient India though the Buddha talked about Great Brahma, who lived in a plane of existence higher than that of sensual gods. He also talked about powerful Brahma Gods even higher than Great Brahma having sway over tens of thousands of worlds. The Buddha described the "way to Brahma" on the basis of cultivating the "divine" abidings of friendliness, compassion, joy in the joy of others and equanimity or supreme unbiased poise of mind. The Buddha was regarded as higher than any of the gods as an emancipated teacher and leader of wisdom - wise enough to have known all the worlds but not subject anymore to rebirth in any of them.
Whereas the Buddha stated that gods could be helpful to humans, there was never any encouragement to beg them for help and to pray to them, thought this sort of devotional practice is common in many Buddhist countries given that Buddhism tends to exist alongside "folk" religions including Hinduism and most traditional religions of this nature involve the supplication of deities of one form or another.
The Buddha never talked about the 31 realms of being explicitly though quite a few of the realms if not all are mentioned in the Sutta and Vinaya Pitakas (some such as the realm of the 33 gods more than others). The commentaries and synthetic traditions collected up all the realms described and systematized them into this hierarchical listing as given here - especially in the Abhidhamma Pitaka composed in its fulness slightly after the Buddha.
The thirty one realms of beings fall into three basic categories: 1) Sense realms 2) Realms of form/fine materiality 3)Immaterial or formless realms. The first category is the one we belong to and practically all sentient animals. Most beings we hear about such as gods, angels, ghosts and hellish creatures also belong to the sense sphere. Beings in the sense realm typically have more than two senses and in the Buddhist context there are 6 senses - eye, ear, nose, tongue, body/tactile and mind. Most of these beings experience all these senses and their objects be they pleasant, unpleasant or neither painful nor pleasant. Typically they enjoy sensory objects like food or music and eschew pain or at least try to. Human beings belong to this realm. Typically there are two sexes in the sense realms and reproduction may require their participation in one form or another, though in the higher sense heavens, gods may be born spontaneously in the adult form.
The thirty one realms of beings can also be divided into four groups. 1) the downfall/hells 2) heavens including the human state 3) form realms and 4) formless realms. Here the first category above, the sense realms has been divided according to whether they are painful or dull states of being or pleasant and wiser states of being. Unlike in some religions, birth in any of these realms is not for ever. Here is the list of the 31 realms:
The downfall/ woeful planes
1. The hells
These are the lowest states of being and in the Abhidhamma, there are eight hells and several minor ones creating a total of around 168 worlds of suffering. Hate is a predominant state of mind that can lead to rebirth in hell where beings are tormented and sensations are generally exclusively painful. Beings in hell imagine that they are going to stay there for ever - just like we can when we are suffering, even though it can pass. Lifespans in these worlds are variable though they can be pretty long.
2. The animal realm
The animal realm is not as bad as the hells but it is regarded as woeful given that animals tend to be deluded to a greater or lesser extent. Furthermore, wild animals are too busy to gain spiritual emancipation or to participate in good or wholesome actions. Whereas there are exceptions, generally animals are not "awake" and may have to endure sufferings beyond their control. The Buddha encouraged kindness towards animals and described previous incarnations where he had been an animal. This realm can be close to our own plane of existence.
Most ghosts we hear about belong to this realm though it also includes typically invisible, sometimes monstrous creatures who generally suffer or lead unfulfilled existences. Ghosts are often depicted with large bellies and small mouths and necks as a sign that they are hungry but cannot ever have enough. Apparently if you develop the divine eye, you can see ghosts - and they share the world with us. Some ghosts may be smarter than animals, but existence here can be unfulfilled. Humans are encouraged to share the fruits of their good actions with ghosts to try and push them onto happier worlds. Greed and clinging is associated with ghostly realms.
A diverse set of beings also described as demons or titans - typically characterized as being jealous of the fruits enjoyed by the blissful gods or beings engaged in fighting or being malicious. Some of these beings are supposed to be quite ugly and they are stated as living in the seas amongst a gamut of abodes.
5. The human realm
Humans exist between the hells and heavens. The word Manussa in Pali (with the same root as man) refers to beings with sharp minds. They are capable of good and bad actions and there is a mixture of pleasure and pain. This realm is one of opportunity to develop and accumulate skillful states of mind. It is a realm where the motivations for actions can be very strong and consequential with the potential of Wisdom (knowing right and wrong, being able to discriminate and "cut off" delusions). Buddhas are always born in the human plane. In the texts the lifespan of humans is described as variable though relatively short. In our context it is around a century.
The first of the heavens - a world with a number of different kinds of beings whose lives are underpinned by basic morality and goodness. There are supposed to be four great kings that are like the guardians of the worlds/directions in their vicinity. This is the realm into which "fairies, elves, goblins, pixies" would belong and a plethora of basically trustworthy beings that tend to populate books by Tolkien and the fairy stories of diverse cultures. Maximum lifespans are up to 9 million years.
This is a heaven presided by 33 gods - the chief of them is Sakka, a king of gods. Typically this is the first of a major series of heavens with beings who experience exclusively pleasant sensations. They live surrounded by beauty, wealth and joy characterized by fluidity and rectitude of mind and body but cannot undertake strong good actions as the motivations are weak (just as when you are on holiday, you may not want to bother with solving complicated problems). However, there is the opportunity to increase your spiritual potential. There are many stories about this realm based around palaces and gardens. Lifespans go up to 36 million years.
These two are the highest sense plane heavens and Gods who have power over the creations of others represent very powerful beings lording over the creations in the realms below. I'm reminded of great film directors. The lifespans range from 2 to 9 billion years. Beyond this point it is hard to travel given that sensory pleasures can bind beings but those who succeed experience pleasure beyond sensory bliss.
The form realms are accomplished on the basis of developing skillful mental unification/concentration centered on an object like the breath, or states of loving kindness or compassion. In these worlds, there is just one sex or no sex and the beings tend to only have two senses, those of sight and hearing. They don't need to eat material foods as such and subsist on states of mental bliss with bodies of subtler materiality than the lower gods. In these realms and those following, you are born spontaneously into these realms with no parents as such.
There are four levels of concentration or Jhana. Corresponding with each of the first three Jhanas are three worlds each and for the fourth Jhana seven worlds making a total of 16 heavens referred to as the worlds of Brahma. Lifespans are measured in aeons.
In the first Jhana plane are the heavens of Brahma's retinue, Brahma's ministers and great Brahma. Great Brahma has a lifespan of 1 aeon. In the second Jhana plane are the heavens of gods of minor lustre, infinite lustre and radiant lustre (described as radiance). In the third Jhana plane are the heavens of minor aura, infinite aura and steady aura. In the fourth Jhana plane are the heavens - Brahmas of great reward, mindless beings (these beings only have bodies and their mental activities are suspended for that duration), durable gods, serene gods, beautiful gods, clear sighted gods and the eldest gods (where non returners or Anagamis are born - the third level of enlightenment, never returners cannot return to the sense realms and will achieve full liberation from these Pure Abodes (The Buddha to be was never born here)). The last of these realms supports lifespans of 16,000 aeons.
The higher Jhanas are simpler and more subtle than the lower ones. They are associated with psychic abilities like mind reading, traveling between worlds instantly, transforming matter among of plethora of others.
The formless realms are more subtle than the form realms and these beings are devoid of bodies and exist as mind only. The realms are the sphere of infinite space, the sphere of infinite consciousness, the sphere of no-thing, the sphere of neither perception nor non perception. The lifespans are practically infinite up to 84,000 aeons which is hundreds of times greater than the age of the present universe as estimated by scientists.
The form and formless realms can only be accessed by developing meditation. The remaining heavens can be accessed by good conduct of body speech and mind. The human realm is a sort of neutral state which can lead you to hells or heavens depending on your actions and associations.