Dharma, or ";duty," is at the center of the Hindu way of thinking; with its stress on personal responsibility, the concept gives to Hinduism its particular stress on the centrality of humanity in the universe. The word comes from the Sanskrit word, dhri , which means "to sustain." It is dharma that sustains the cosmic order (Rita) of the universe.

 Explicitly allied with the doctrine of samsara, the cycle of birth and rebirth, is the concept that each action (karma) one takes causes other actions one takes in the future and has been caused by actions in the past. The life into which one is born has been caused by actions one has taken in the past; this is how Rita operates in the moral world. The life which one is born into can be related to other people's lives in terms of social position (the "four colors" or castes), occupation (jati ), or stage of life or maturity. Each of these—social position, occupation, stage of life—has prescribed duties and obligations associated with them. Since one assumes this life as a necessary consequence of previous lives and previous actions, it follows that one should perform the prescribed duties of your life unflaggingly. Therefore, social organization and the functions and obligations of each social group has in Hinduism a broader justification than mere efficacy; one's life and the specific obligations incumbent on it are all manifestations in the physical and moral world of the moral order of the universe itself.

In the Bhagavadgita , Krishna teaches that one performs one's duty whether one intends to or not; dharma in this dialogue takes on a broader meaning to include knowledge. Although the actions one takes are predetermined by previous actions (which makes each human being somewhat like an automaton), one can still choose the manner in which one takes those actions. In the Gita , the manner in which one can take action is divided into three sets: dark inertia, passion, and lucidity. While duty is predecided, the individual relation to that duty (dark inertia, passion, lucidity) is within each person's control.