According to the Sankhya philosophy, nature is composed of three forces called, in Sanskrit, Sattva, Rajas and Tamas. These as manifested in the physical world are what we may call equilibrium, activity and inertness. Tamas is typified as darkness or inactivity; Rajas is activity, expressed as attraction or repulsion; and Sattva is the equilibrium of the two.

In every man there are these three forces. Sometimes Tamas prevails; we become lazy; we cannot move; we are inactive, bound down by certain ideas or by mere dullness. At other times activity prevails and at still other times that calm balancing of both. Again, in different men, one of these forces is generally predominant. The characteristic of one man is inactivity, dullness and laziness; that of another, activity, power, manifestation of energy; and in still another we find the sweetness, calmness and gentleness, which are due to the balancing of both action and inaction. So in all creation—in animals, plants and men—we find the more or less typical manifestation of all these different forces.
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Karma-Yoga has specially to deal with these three factors. By teaching what they are and how to employ them it helps us to do our work better. Human society is a graded organisation. We all know about morality, and we all know about duty, but at the same time we find that in different countries the significance of morality varies greatly. What is regarded as moral in one country, may in another be considered perfectly immoral. For instance, in one country cousins may marry; in another, it is thought to be very immoral; in one, men may marry their sisters-in-law; in another, it is

regarded as immoral; in one country people may marry only once; in another, many times; and so forth. Similarly in all other departments of morality we find the standard varies greatly; yet we have the idea that there must be a universal standard of morality.

So it is with duty. The idea of duty varies much among different nations: in one country, if a man does not do certain things, people will say he has acted wrongly; while if he does those very things in another country, people will say that he did not act rightly; and yet we know that there must be some universal idea of duty.