The Indian thinkers viewed the world as an illusion and deliberated deeply on the relation between the soul and god.
Indeed, philosophers of no other country delved so deeply into this problem as did the Indians.
Ancient India is considered famous for its contribution to philosophy and spiritualism, but the Indians also developed a materialistic view of the world.
In the six systems of philosophy that Indians created we find elements of materialistic philosophy in the Samkhya system of Kapila, who was born around 580 BC. He believed that the soul can attain liberation only through real knowledge, which can be acquired through perception, inference, and hearing.
The Samkhya system does not recognize the existence of god. According to it, the world has been created not by god but by nature, and the world and human life are regulated by natural forces. The development of logic may have helped the Samkhya system. Prior to the fifth century, logic was not a well-established discipline. The Nyaya Sutra seems to have been compiled around ad 400. It mentions four proofs orpramanas comprising perception, inference, comparison, and testimony.
We find detailed discussions regarding valid and invalid knowledge, and aspects of each kind of proof are treated in detail. Although debating devices were used in theological disputes, they could not have been developed in isolation from other disputes, including land disputes.
Materialistic philosophy received the greatest impetus from Charvaka, who lived in about the sixth century BC. The philosophy that he propounded is known as Lokayata. He argued that what is not experienced by man through his sensory organs does not really exist, which implies that gods do not exist.
However, with the decline in trade, handicrafts, and urbanism, the idealist system of philosophy came to the fore. The idealist system taught that the world is an illusion. People were asked by the Upanishads to abandon the world and to strive for real knowledge.
Western thinkers have taken to the teachings of the Upanishads because they are unable to solve the human problems created by modern technology. The famous German philosopher, Schopenhauer, found in his philosophy a place for the Vedas and the Upanishads. He used to say that the Upanishads consoled him in this life and would also console him after death.