According to Indian tradition, society is divided into four categories or castes known as brahmin (the priesthood), kshatriya (the warrior caste), vaishya (the merchant caste) and shudra (the labourers). Even if today these categories seem to be disappearing as social divisions, they remain present unconsciously and represent different qualities of being which have meaning for us no matter what our profession or place in society may be.

How do these categories apply to the discipline of yoga? A beginner must work hard and sweat in order to learn. This is the quality of the shudra. When he has become an experienced student, he will express himself by teaching to earn his living through yoga. This is the state of mind of the merchant or trader and so represents the quality of the vaishya. Then he will enter into competition with his colleagues–maybe he will even teach with feelings of pride and superiorty. This reveals the martial chiaracter of the kshatriya. At the final stage, the seeker penetrates deeply into the essence of yoga to draw from it the nectar of spiritual realisation. This is the religious fervour of yoga, and when one acts on the basis of this feeling, one’s practice of yoga is that of a brahmin.

These four divisions occur in many other areas. Thus, the life of the human being, considered as a hundred years, is divided into four consecutive twenty-five year periods called ashramas. These are respectively brahmacharya, the phase of general and religious education; garhasthya, or life in the home; vanaprastha, or preparation for renunciation of family activities; and sannyasa, or detachment from the affairs of this world and attachment to the service of the Lord.

The sages of ancient times also distinguished four aims of life, or purusharthas, and recommend the pursuit of one of the four aims of life during each of the four ashramas. The four aims of life are dharma, the science of ethical, social and moral obligations; artha, the acquisition of worldly goods; kama, the pleasures of life; and moksa, freedom or felicity.