The Caraka Samhita, India’s ancient text on Ayurvedic medicine, states that there exist three natural instincts of human life. 
THE DESIRE TO LIVE
This is the most fundamental and basic instinct of life. Life desires continued life. The instinct to survive is what keeps us going when times get difficult. As a person evolves a bit more, this instinct provides the motivation to plan ahead for longevity. Thus, a person tries to take the best possible care of him or herself. The pursuit of longevity is the initial motivation behind exercise, eating a healthy diet, taking supplements and making lifestyle changes. Only later do these actions take on a higher meaning; that of living harmoniously for the purpose of fulfilling the higher aims of the four goals of life and ultimately the liberation of the soul.
THE DESIRE TO EARN
Some form of monetary value has always been present in the experience of mankind. Whether accumulating cows and goats, gold and jewels, or money, the desire to earn has always been present. Earning allows a person to pursue the goal of artha.
In modern times, those of a communal or collective mindset often look upon money as a source of the world’s troubles. Hence, some are of the mindset that money is “the root of all evil.” Earning money through right livelihood and in service to humanity is a desirable trait in a person. When a person places too much emphasis on money and not enough on service however, that person becomes greedy.
THE DESIRE TO PERFORM VIRTUOUS ACTS
This desire is deep within human nature. It springs from the same place as the desire for moksha. For as long as the soul has been whispering in the mind of mankind, mankind has desired and taken action to make the world a better place for all people.
Excerpt from “Principles of Ayurvedic Medicine,” by Dr. Marc Halpern, Founder of the California College of Ayurveda