As Peter Russell explains about atheism in his book "From Science to God"

No God

Along with the transition from polytheism to monotheism came the emergence of atheism, or “no God”. It might seem contradictory to have a religion without s god, but several major traditions have arisen around this time.


In India, in the sixth century B.C., a young prince named Mahavira became disenchanted with the traditional Vedic religion, which advocated the sacrifice of innocent animals, the performance of meaningless rituals, and the belief of fictitious man made gods. Renouncing the grand lifestyle of his palace, he wandered penniless for thirteen years seeking a better way. Then one day while absorbed in deep meditation, he experienced a unity with all creation and a liberation from worldly woes. He consequently proclaimed himself Jina, “the Conqueror” – the conqueror of the mind – and encouraged his followers, the Jains, to attain a similar liberation through righteous living, nonviolence, and harmlessness.


Shortly afterward, another Indian prince, Siddhartha Gautama, likewise left the luxury of his palace and set out to find a way to end suffering. Six years later, in deep meditation, he too attained liberation, and was called Buddha – “the Awakened One”. Buddha realized that suffering was self-created and unnecessary, and began teaching others how to wake up and find true freedom.


During the same period, two atheistic religions arose in China. Like Jina and Buddha, Lao-Tzu and Confucious both taught that people could discover truth and find inner peace without believing in any deity. They too, advocated lives of simplicity, virtue, honesty, and above all, kindness.


This fourth religious paradigm lacked some of the benefits provided by a benevolent deity. There is no longer a supernatural agent to intervene in human affairs; one’s destiny is now in ones own hands. But much of the rest remained. Love, kindness, and right living were important; salvation from the sufferings of the world was still possible. In a sense there was still even a devil, but now the devil was within oneself. The goal was to liberate the mind from its self-imposed limitations- from desires, attachments, delusions and a false sense of self.


- Peter Russell.