Selfishness comes into existence owing to the tendency of desires to find fulfillment in action and experience. It is born of fundamental ignorance about one’s own true nature. Human consciousness is clouded by the accumulation of various types of impressions deposited by the long course of the evolution of consciousness.
These impressions express themselves as desires, and the range of the operation of consciousness is strictly limited by these desires. The sanskaras, or impressions, form an enclosure around the possible field of consciousness. The circle of sanskaras constitutes that limited area in which alone the individual consciousness can be focused.
With some of the desires action is merely latent, but others can actually translate themselves into action. The capacity of a desire to find expression in conduct depends upon the intensity and the amount of sanskaras connected with it. When a desire gathers sufficient strength, it projects itself into action in order to get fulfilled.
-Extracted from ‘Discourses’, 7th Ed, p 10