The Theravāda school is ultimately derived from the Vibhajjavāda (or 'doctrine of analysis') grouping which emerged amongst the older Sthavira (or 'teaching of the Elders') group at the time of the Third Buddhist Council around 250 BCE, during the reign of Emperor Asoka in India. Vibhajjavadins saw themselves as the continuation of orthodox Sthaviras and after the Third Council continued to refer to their school as the Sthaviras/Theras ('The Elders'), their doctrines were probably similar to the older Sthaviras but were not completely identical. After the Third Council geographical distance led to the Vibhajjavādins gradually evolving into four groups: the Mahīśāsaka, Kāśyapīya, Dharmaguptaka and the Tāmraparnīya. The Theravada is descended from the Tāmraparnīya, which means 'the Sri Lankan lineage'. Some sources claim that only the Theravada actually evolved directly from the Vibhajjavādins.
The earliest available teachings of the Buddha are to be found in Pali literature and belongs to the school of the Theravadins, who may be called the most orthodox school of Buddhism. This school admits the human characteristics of the Buddha, and is characterised by a psychological understanding of human nature; and emphasises a meditative approach to the transformation of consciousness. The teaching of the Buddha according to this school is very plain. He asks us to 'abstain from all kinds of evil, to accumulate all that is good and to purify our mind'. These can be accomplished by The Three Trainings: the development of ethical conduct, meditation and insight-wisdom.
The philosophy of this school is that all worldly phenomena are subject to three characteristics - they are impermanent and transient; unsatisfactory and that there is nothing in them which can be called one's own, nothing substantial, nothing permanent. All compounded things are made up of two elements - the non-material part and the material part. They are further described as consisting of nothing but five constituent groups, namely the material quality, and the four non-material qualities - sensations, perception, mental formatives and consciousness. When that perfected state of insight is reached, i.e. Nibanna, that person is a 'worthy person' an Arhat. The life of the Arhat is the ideal of the followers of this school, a life where all (future) birth is at an end, where the holy life is fully achieved, where all that has to be done has been done, and there is no more returning to the worldly life'.
The name of Tamraparniya was given to the Sri Lankan lineage in India but there is no indication that this referred to any change in doctrine or scripture from the Vibhajjavadins, since the name points only to geographical location. The Theravadin accounts of its own origins mention that it received the teachings that were agreed upon during the Third Buddhist Council, and these teachings were known as the Vibhajjavada. In the 7th century, Chinese pilgrims Xuanzang and Yi Jing refer to the Buddhist school in Sri Lanka as ‘Sthavira’. In ancient India, those schools that used Sanskrit as their religious language referred to this school as the 'Sthaviras', but those that use Pali as their religious language referred to this school as the 'Theras'. Both 'Sthaviras' (Sanskrit) and 'Theras' (Pali) both literally mean 'The Elders'. The school has been using the name 'Theravada' for itself in a written form since at least the fourth century CE when the term appears in the Dipavamsa.
There is little information about the later history of Theravada Buddhism in India, and it is not known when it disappeared in its country of origin.
According to Sinhalese tradition, Buddhism was first brought to Sri Lanka by Mahinda, who is believed to have been the son of the Mauryan emperor Asoka, in the third century BCE, as a part of the missionary activities of the Asokan era. In Sri Lanka, Mahinda established the Mahavihara Monastery of Anuradhapura. Later it became divided into three subgroups, known after their monastic centers as the Mahavihara, the Abhayagirivihara, and the Jetavanavihara. In 1164, with the guidance of two monks from a forest branch of the Mahavihara, Sri Lanka King reunited all bhikkhus in Sri Lanka into the orthodox Mahavihara school.
A few years after the arrival of Mahinda, Sanghamitta, who is also believed to be the daughter of Emperor Asoka, came to Sri Lanka. She started the first nun order in Sri Lanka, but the nun order died out in Sri Lanka in the 11th century and in Burma in the 13th. In 429 CE, on the request of China's emperor nuns from Anuradhapura were sent to China to establish the Nun Order. The order was then spread to Korea. In 1996, 11 selected Sri Lanka nuns were ordained fully as Bhikkhunis by a team of Theravada monks in concert with a team of Korean Nuns in India. There is disagreement among Theravada vinaya authorities as to whether such ordinations are valid. In the last few years the head of the Dambulla chapter of the Siyam Nikaya in Sri Lanka has carried out ordination ceremonies for hundreds of nuns. This has been criticized by some other leading figures in the Siyam Nikaya and Amarapura Nikaya, and the governing council of Burmese Buddhism has declared that there can be no valid ordination of nuns in modern times, though some Burmese monks disagree with this.
During the Asoka reign period, a missionary was also sent to Suvannabhumi where two monks Sona and Uttara, are said to have proceeded. Scholar opinions differ as to where exactly this land of Suvannabhumi is located, but Suvannabhumi is believed to be located somewhere in the area which now includes lower Myanmar, Thailand, Laos, Cambodia and Malay peninsula.
The Mon were one of the earliest people to inhabit lower Myanmar and are believed to have been Theravadin since 3rd century BCE. Archaeological findings have shown that the Mon had close contact with South India and Sri Lanka. The Burmese adopted the Mon religion and writing script (which is also used there as Pali script) when they conquered Thaton the Mon Kingdom in 1057. According to the local traditions, this was the area of Suvarnabhumi that was visited by missionaries from the Asokan court. The Mon were also one of the earliest people to inhabit Thailand. The Thai adopted the Mon religion when they conquered Hariphunchai, the Mon Kingdom in 1292.
However, despite its success in Southeast Asia, Theravada Buddhism was never very successful in China,except in a few small areas bordering Theravada countries. Chinese Buddhism was always predominantly Mahayana, and so in the Chinese, Tibetan, Korean, Japanese, and Mongolian languages, and in many Western works on Buddhism, Theravada and the other traditional schools of Buddhism are referred to as Hinayana, "Lesser Vehicle," in contrast to Mahayana, "Greater Vehicle." However, "Hinayana" is a Mahayana term, not a self-description of Theravada or any other Buddhist school. Scholars are uncertain as to whether "Hinayana" was originally a derogatory term or a descriptive one, but in modern contexts Theravada Buddhists often consider it offensive.
Theravada promotes the concept of Vibhajjavada (Pali), literally "Teaching of Analysis." This doctrine says that insight must come from the aspirant's experience, critical investigation, and reasoning instead of by blind faith; however, the scriptures of the Theravadin tradition also emphasize heeding the advice of the wise, considering such advice and evaluation of one's own experiences to be the two tests by which practices should be judged.
In Theravada, the cause of human existence and suffering (dukkha) is identified as the craving (tanha), which carried with it the defilements (which are anger, ill will, aversion, greed, jealousy, conceit, hatred, fear, sensual desire, obsession, passion, irritation, distraction, vengeance, depression, anxiety, clinging to the body, etc.). The defilements level can be coarse, medium, and subtle. It is a phenomenon that frequently arises, remains temporarily and then vanishes. The defilements are said to be not only harming oneself, they may also harm others. They are also said to be the driving force behind all inhumanities a human being can commit.
Theravadins believe these defilements are the habits born of ignorance (avijja) which infest the minds of all unenlightened beings. It is believed that unenlightened beings assume those mental defilements as their own “Self”, clinging to them through ignorance of the truth. But in reality, those mental defilements are nothing more than parasites that have infested the mind and create suffering and stress. It is also believed that unenlightened beings cling to the body, assuming it as their own “Self”, but in reality the body is an impermanent phenomenon formed from the 4 elements (Earth, Fire, Water & Air) and after death the body will decompose and disperse. The mental defilements' frequent instigation and manipulation of the mind is believed to have prevented the mind from seeing the truth of reality.
It is believed that in order to be free from suffering and stress these defilements need to be permanently uprooted. Initially the defilements are restrained through mindfulness to prevent them from taking over the mind and bodily action. They are then uprooted through internal investigation, analyzing, experiencing and understanding the true nature of those defilements by using jhana. This process needs to be repeated for each and every defilement. The practice will then lead the meditator to realize the Four Noble Truths, Enlightenment and Nibbana. Nibbana is the ultimate goal of Theravadins. Nibbana is said to be the perfect bliss and the person is liberated from the repeated cycle of birth, illness, aging and death. This practice is said to be the path that will lead its practitioner toward self-awakening and liberation from the repeated cycle of birth, illness, aging and death.
Theravadins believe that every individual is personally responsible for their own self-awakening and liberation, as they are the ones that were responsible for their own actions and consequences (kamma). Simply hearing or learning about the ultimate truth (or "reality") is not enough, the awakening can only be achieved if the individual personally knows it by direct experience and realizes it for themselves as the ultimate truth. They will have to follow and practice the Noble Eightfold Path as taught by the Buddha for the realization and verification of the ultimate truth. In Theravada belief, Buddhas, gods or deities are incapable of giving a human being the awakening or lifting them from the state of repeated cycle of birth, illness, aging and death (samsara). For Theravadins, Buddha is only a Teacher of the Noble Eightfold Path, while gods or deities are still subject to anger, jealousy, hatred, vengeance, craving, greed and delusion.
It is believed that some people who practice with earnestness and zeal can attain Nibbana within a single lifetime, as did many of the first few generations of Buddha's disciples. For others, the process may take multiple lifetimes, with the individual reaching higher and higher states of realization. Those that have attained Nibbana are called Arahant, literally "Winner of Nibbana". It is believed that the Nibbana is most quickly attained as a disciple of Buddha.
In Theravada, the Nibbana attained by Arahants is believed to be identical to that attained by the Buddha himself, as there is only one type of Nibbana. Buddha was superior to Arahants because the Buddha had discovered the path all by himself, and was able to teach others (ie; metaphorically turning the wheel of Dhamma). Arahants, on the other hand, attained Nibbana due in part to the Buddha's teachings. Theravadins revere the Buddha as a single supremely gifted person but do recognize the existence of other such Buddhas in the distant past and future. Maitreya (Pali: Metteyya), for example, is mentioned very briefly in the Pali Canon as a Buddha who will come in the distant future.
Traditionally Theravadins can either have the conviction (or "faith") in the Buddha's teaching and practice the minor precepts in the hope of gaining some minor benefits or they can investigate and verify by direct experience the truth of the Buddha's teaching by practicing the jhana which is part of the Noble Eightfold Path for their own Enlightenment.
In the Pali Canon discourses, the Buddha frequently instructs his disciples to practice anapanasati (mindfulness with breathing) as the base for samadhi (concentration) in order to establish and develop jhana (full concentration). Jhana is also the instrument used by the Buddha himself to penetrate the true nature of phenomena (through investigation and direct experience) and to reach Enlightenment. Jhana can be developed from mindfulness with breathing, from visual objects (kasina), and repetition of phrases. The traditional list contains 40 objects of meditation (Kammaṭṭhāna). Meditation on the parts of the body will result in a lessening of attachment to our own bodies and those of others; a reduction of sensual desires occurs. Mettā (loving kindness) generates the feelings of goodwill and happiness toward ourselves and other beings; metta practice serves as an antidote to ill-will and fear. Right Concentration (samma-samadhi) is one of the elements in the Noble Eightfold Path.
Through practice, (Theravadin) practitioners can achieve four degrees of spiritual attainment, which reflect on the state of mind:
Stream-Enterers - Those who have destroyed the first three fetters (false view of self, doubt, and clinging to rites and rituals), will be safe from falling into the states of misery (they will not be born as an animal, peta (ghost), or hell being). At most they will have to be reborn only seven more times before attaining Nibbana.
Once-Returners - Those who have destroyed the three fetters (false view of self, doubt, and clinging to rites and rituals), and the lessening of lust and hatred. They will attain Nibbana after being born once more in the world.
- Those who have destroyed the five lower fetters (that bind beings to the world of the senses). They will never again return to the human world and after they die, they will be born in the high heavenly worlds, there to attain Nibbana.
- Those who have reached Enlightenment, realized Nibbana, and have reached the quality of deathlessness, free from all the fermentations of defilement; whose ignorance, craving and attachments have ended.