Besides the political developments of significance, another far-reaching development was the momentous religious upheaval.
This religious upheaval shook the foundations of the Vedic orthodoxy and gave rise to many heterodox religious movements.
Though there arose eighty-two heterodox religious schools in the Gangetic valley, only Buddhism and Jainism stood the test of time and grew into well-organized popular religions, along with the Sanatana Dharma.
Out of the 82 religious sects, Ajivika and Lokayata deserve notice. They preached materialistic doctrines and ethics. These heterodox sects arose primarily because the Vedic rituals and practices had become unduly elaborate and expensive. Further, the newly emerging socio-politico milieu made the other social groups acquire considerable economic power.
The Kshatriyas, the merchants, the landed aristocrats, the Gahapatis and the Kutumbins began to raise their voice against the birth-based social status and they too began to aspire for a better social status. Thus, the negative attitude towards the existing Varna-based social order, either theoretical or practiced, and the alternative basis of social order propagated by the Buddha and Mahavira attracted these new social groups to favour Buddhism and Jainism against sacrifice and Varna-based social order of the Brahmanical tradition.
The newly emerging peasant communities who appear to have become dominant did not approve the killing of cattle in the sacrifice, as cattle wealth was very essential to supplement agricultural operations. The non-killing or Ahimsa preached by the heterodox sects appears to have made these social groups opt for the heterodox sects. Besides these factors, the patronage extended to trade and commerce in particular by Buddhism and Jainism made the merchants, rich and poor agriculturists and artisans to favour Buddhism and Jainism.
The code of conduct prescribed for lay people by these new religions appeared to be more practical than performing protracted rites through the Brahmin priest. These causes led to the new socio-economic and political milieu that arose in the 6th century BC in the Gangetic valley.
India witnessed the birth of two outstanding teachers and thinkers, who moulded not only the way of life of the natives of Bharatavarsha but also of the entire humanity largely. They were Gautama, the Buddha, ‘the enlightened’, ‘the awakened’, ‘the light of Asia’ and ‘the light of the World’, the founder of Buddhism, and Nighantanata Putta or Mahavira, the 24th Thirthankara, well known as Jaina\who popularized Jainism. Both, by their teachings and life made India a worthy nation among the comity of nations. Their teachings were as relevant at that time as they are today.
The Buddha through his preaching’s provided a new dimension, the urge for social equality. Both the teachers also believed in the concept of constant travelling and preaching the principles. While the Buddha advocated a middle path, Mahavira advocated strict and extreme asceticism.
Today, both Buddhism and Jainism are two living faiths for millions of devotees, like any other religion. Some think of Buddhism and Jainism as ‘the two angry daughters of Hinduism’ as there are certain similarities between those heterodox sects and the Brahmanical religion. If Hinduism is a way of life, these two religions also advocate a way of life. Both these religious doctrines are codified into texts to be scrupulously followed by their devotees and practitioners.
There is also a view that Buddhism was a social movement that took the urban side in the contemporary rural-urban philosophical ideological struggle. For V.K. Thakur, Buddhism was definitely a religion seemingly fighting for the privileges of the powerful emerging urban groups hitherto denied any social recognition and prestige in a society dominated by the orthodox Brahmanical values.
It is interesting to note that though both were contemporaries, neither the Buddhist literary tradition nor the Jaina literary texts record the meeting of their great teachers. There are again several new perceptions about the origin and growth of the heterodox religions.
Some scholars today question the premise of heterodox sects rising as a reaction against Vedic traditions. The Vedic tradition during the birth of Buddhism and Jainism was still in state of flux and was yet to develop a strong ethic for or against a given religious percept.
Such fullness on the Vedic tradition’s behalf was reached only much later in history. Internal evidence gleaned from the Buddhist and Jaina texts of the early historic period do not seem to have any apathy towards the Vedic traditions. It may be said that heterodoxy, even according to the Vedic texts, was a very ancient system that ran parallel to the growth orthodoxy, as assigned to some sections of the Vedic liturgy like the Brahmanas.