1. The origin of the Mahayana Buddhism
Many think that the origin of the Mahayana Buddhism is a mystery. Suddenly, there appeared a number of sutras, all disagreeing to certain extent with the traditional conservative Buddhism doctrines, but all claiming to be Buddha-vacana (Buddha’s words), and frequently referring to themselves as the Mahayana. The historical record shows that Mahayana emerged as a separate school around the beginning of Common Era. However, it most likely had been developing gradually for a long time before that.
Akira Hirakawa claimed that the Mahayana Buddhism arose outside the monastic context, and that it is originated from the stupa worship among a group of lay people. His theory was dominant for years, especially among the Japanese scholars, before it was rejected by mainstream scholars. The main point of this theory is that the Mahayana grew among an order of Bodhisattvas, composed of mainly lay people, centered on stupa worship.
Hirakawa’s theory were later challenged by some western scholars, for example, accoding to Paul Williams, Schopen claimed that early Mahayana was centered on a number of book cults, groups of followers studied and worshipped particular sutras, instead of stupa. Schopen also claimed that majority of those associated with making donations and worshiping stupas were actually monks, not laymen. Finally, Hirakawa’s theory was largely rejected in late 1980s.
Some scholars, such as Lamontte and Conze, have suggested that Mahayana is primarily an offspring of Mahasanghika, a now-extinct Buddhist sect formed about 320 BCE. Mahasanghika developed the idea of the transcendent nature of a Buddha, and some form of the doctrine of shunyata, or "emptiness."
Ven. KL Dhammajoti finds the link between the Abhidharma and the Mahayana. Dhammajoti claims that the term of Mahayana was not originally coined to be as the contrast of Hinayana. It was actually interchangeable with Boshisattva-yana and Boddha-yana. Dhammajoti studied Abhidharma-mahavibhasa and found that the Mahayana threefold scheme: sravaka-yana, pratyebuddha-yana, bodhisattva-yana, was derived form earlier pre-Mahayana scheme of sravaka-yana, pratyebuddha-yana and boddha-yana. And some of the distinctive buddhological doctrines in Mahayana, such as great compassion and perfect wisdom, had already been well articulated in Abhidharma.
Other scholars found the influences of other earlier Buddhism schools, for example, Andrew Rawlinson claims that Mahayana used varied sources in order to flesh out its teachings, such as:
Reinterpretations of Nikayas;
Speculations of description from more progressive schools, e.g. Mahasamghiksas;
Reassessment of traditional techniques, e.g. Abhidharma practices;
Inclusion of non-exclusive practices, e.g. paramitas, stupa worships;
And even acceptance of foreign influences. Etc.
It's fair to say that Mahayana developed from various earliest schools of Buddhism, in a gradual way. Heinrich Dumoulin wrote that "Traces of Mahayana teachings appear already in the oldest Buddhist scriptures. Contemporary scholarship is inclined to view the transition of Mahayana as a gradual process hardly noticed by people at the time."
And Mahayana Buddhism has a multiplicity of sources. We cannot say that Mahayana Buddhism originated exclusively among certain laity, or the Mahasamghikas, or certain Abhidhamists, or certain rebel monks, actually, all of these had their own contributions. The contribution of each group interacted dynamically and resulted in the emergence of the Mahayana Buddhism.
2. Mahayana vs. Hinayana
As discussed, Mahayana Buddhism was not emerged in one day, it was a gradual process. There are evidences that “Mahayana appears to have been an uninfluential minority interest for centuries until well into the Common Era”. During this gradual process, Mahayana Buddhism had been criticized by the adherents of the pre-Mahayana schools. One of the key attacks from the non-Mahayanists was that the genuineness of the Mahayana sutras is questionable. The Mahayanists had to defend themselves. The Mahayana-sutralamkara (大乘莊嚴經論) illustrates this. This text, which was wrote in late 3rd century or early 4th century, enumerates eight reasons that Mahayana teachings are Buddha-vacana.
On the other hand, the Mahayanists fight back by accusing the adherents of the pre-Mahayana schools for being narrow-minded egoists. The debate got heated and it is believed that some Mahayanists coined the word “Hinayana” to call their opponents. As everyone knows, “yana” in Pali or Sanskrit means “vehicle”, and “Maha” means “big, great”, and “Hina” means “small or lesser”. So “Mahayana” means “Great Vehicle” and “Hinayana” means “Lesser Vehicle”. The vehicle definition mainly refers to the number of sentient beings that are helped before one enter final Nirvana.
The highest attainment in “Hinayana” schools is Arahant. The adherents of these schools concern mainly their own enlightenment. Arahant would enter Nirvana upon death, and stop helping other sentient beings. In contrast, the highest attainment in Mahayana is Buddhahood. A person striving to do so is called a Bodhisattva, who has vowed to help uncountable sentient beings (to be enlightened), he will not enter Nirvana even when he has the ability to do so.
Non-Mahayana schools think the term “Hinayana” is a highly derogatory term, because it does not simply mean “Lesser vehicle”, but could also mean “low, undesirable, despicable”. In 1950, the World Fellowship of Buddhists unanimously decided the term “Hinayana” should not be used to refer to Buddhism existing in southern countries, such as Sri Lanka, Thailand, Burma, Combodia, etc. So, there are no existing “Hinayana” schools. The conservative Buddhism in these southern countries should be called “Theravada”.
In the history, the term of “Hinayana” used by Mahayanists to call the pre-Mahayana conservative schools. As Paul Williams pointed out, Buddhism has its character of doctrinal diversity. There are no Buddhism popes, no creeds, and Shakyamuni did not assign anyone to have full power over the monk’s order. After Parinibbana, the Sangha first split into Sthaviravada and Mahasamghika, and then further divided into various schools. According to A. K. Warder, eighteen conservative schools or arose sometimes between one hundred to two hundred years after Parinibbana (between 2ed and 3rd Buddhist Councils). But the number 18 might be merely conventional, because difference sources give different lists of them, and the number could be double. These conservative schools were called “Hinayana” by followers of Mahayana. Most of these schools have disappeared with only Theravada still popular in the Sri Lanka and other southern countries. As the term “Hinayana” is derogatory, it is suggested to use Conservative Schools, early Schools or Nikayas instead.
Although the various early schools of Buddhism are sometimes loosely classified as "Hinayana” in modern times, this is not necessarily accurate. Actually, Mahayana is more like the set of ideals and doctrines for bodhisattvas than a separate sect of Buddhism. Paul Williams has noted that the Mahayana never had nor ever attempted to have a separate Vinaya or ordination lineage from the early schools of Buddhism, and therefore each monk or nun adhering to the Mahayana formally belonged to an early school. In this sense, Mahayana was never a separate rival sect of the early schools. Actually, as Xuan Zang noticed, both Mahayana and non-Mahayana monks in India often lived in the same monasteries side by side.
1. Paul Williams Mahayana Buddhism: The Doctrinal Foundations Routledge 1989
2. A. K Warder Indian Buddhism Delhi, Motilal Banarsidass, third revised edition, 2000
3. Andrew Rawlinson “The Problem of the Origin of the Mahayana” in Traditions in Contact and Change Waterloo Wilfrid Laurier University Press 1983
4. KL Dhammajoti From Abhidharma to Mahayana: Remarks on the early Abhidharma doctrine of the three yanas Journal of Buddhist Studies, Vol.IX, 2011 Sri Lanka Center of Buddhist Studies
5. Dumoulin Zen Buddhism: A History, Vol. 1, India and China Macmillan 1994
6. Bro Chan Khoon San & Kare A. Lie No Hinayana in Buddhiam Bro Chan Khoon San, Malaysia 2011
7. KL Dhammajoti lecture notes for the course of Mahayana Buddhism at Hong Kong University
 KL Dhammajoti From Abhidharma to Mahayana: Remarks on the early Abhidharma doctrine of the three yanas Journal of Buddhist Studies, Vol.IX, 2011 Sri Lanka Center of Buddhist Studies p153
 Paul Williams Mahayana Buddhism: The Doctrinal Foundations Routledge 1989 p22
 KL Dhammajoti From Abhidharma to Mahayana: Remarks on the early Abhidharma doctrine of the three yanas Journal of Buddhist Studies, Vol.IX, 2011 Sri Lanka Center of Buddhist Studies
 Andrew Rawlinson “The Problem of the Origin of the Mahayana” in Traditions in Contact and Change Waterloo Wilfrid Laurier University Press 1983 pp163-170
 Dumoulin Zen Buddhism: A History, Vol. 1, India and China Macmillan 1994, p28
 Paul Williams Mahayana Buddhism: The Doctrinal Foundations Routledge 1989 p6
 Bro Chan Khoon San & Kare A. Lie No Hinayana in Buddhism Bro Chan Khoon San, Malaysia 2011 p3
 A. K Warder Indian Buddhism Delhi, Motilal Banarsidass, third revised edition, 2000 pp277-332
 Paul Williams Mahayana Buddhism: The Doctrinal Foundations Routledge 1989 p5