The author has demonstrated strong and important naturalistic elements and attitudes in Indian systems of Philosophy down to the sixth century. Yet with such an auspicious development, with a longer continuous tradition than Greece had, as misfortune struck India, first, during the period of continuous conflict among the principalities (500-1000), then, during the Muslim Theological supremacy (1000-1650), and finally, during the colonial age of European trade rivalry (1650-1947), naturalism in India was nearly totally replaced by various forms of idealism which tried to make pleasant an imaginary life when the natural one was frequently intolerable. As naturalism grew increasingly stronger in Europe (and Japan), it grew markedly more feeble in India (and China), until in the twentieth century, particularly since India gained Independence (1947), it again began to raise its ancient and honourable standard in the new India.
Part of India's attempt to understand nature can be told in the history of Indian naturalistic and proto-scientific thought. The author has tried here to sketch the main outlines of Indian naturalism as it appears in both systematic and unsystematic speculation before its decline in the Indian Middle Ages, which began about the time of Muhammad.