Man occupies the central position in the philosophical thinking of Radhakrishnan. Most of his ideas were developed by his extensive dependence on the philosophy of the Upanishads. The Prasthana Traya consists of the later three, the Upanishads, the Gita and the Brahma Sutra are generally the important source on which the Indian thought, and particularly the Vedantic philosophy depends. Radhakrishnan was such a philosopher who was born in an age when the first waves of Indian revivalism are fully in their actualization. The age had much a thing to speak of the Indian scriptures and of justifications of authority. And Radhakrishnan did not fail to reflect the same. Radhakrishnan extensively refers to the Upanishads for his fundamental ideas of man and his ethical idealism. Every religion will be fully charged with the ethical foundation as its source of inspiration. The feelings of purity and the merit of his actions which may lead man to his next birth becomes the principle of human motivation. Radhakrishnan justifies most of the ethical precepts and moral principles of his idealistic philosophy. Man shall make room to the spirit within which the spirit he tries to manifest through the intuitive visions in his religious experiences. Radhakrishnan’s orientation was towards the spiritual means rather than the materialistic ends. He was much pained by the world wars of the West. In his book Religion and Society  he expresses his concern about the modern society’s crisis. In his address at the Free University of Brussels Radhakrishnan says:

The future of mankind depends on the future of man, on his spirit, on his approach to the problems which face him. If he relies on force and adopts a military approach, the future is bleak indeed; if, on the other hand, he believes in the spirit, he will prosper⁹.