Finally, even birth and death are traced to this mysterious cause which cannot be directly seen, as it is involved in the seeing consciousness itself. There is nothing which is not involved in this triadic relation, in any stage of creation. Herein he makes the principle of deity unavoidable in the evolutionary process on a nisus to progress upwards. It is this presiding principle which the Bhagavadgita confirms as the final deciding factor in all actions and processes of man and the world. The crystallisation of this doctrine is the great religious theology of India, which posits various deities as the guardians of the cosmos and sets forth rules of their worship in the interest of man's march towards his great destiny.
Theology is an essential part of religion, which is a name for philosophy in practice.
The rules of conduct are a part of the religious way of life. The Smritis are the codes which lay down the laws of human behaviour in one's personal capacity as well as in society. It is the intention of the Smritis to make explicit the forms of righteousness as they manifest themselves in practical life, which are only implicit in the principles of Satya and Rita or in the account of creation given in the Upanishads. These texts not only deal with the ethical problems of man as an individual and as a member of a family or of society in general, but also dilate upon the rules of administration. The Smritis of Manu, Yajnavalkya and Parasara, the Santi-Parva of the Mahabharata and the Arthasastra of Kautilya are the primary sources of information on this subject.