Humankind is developing evolutionally starting from animal desires. Animal desires are desires of our body: for food, shelter, family, and sex. They all pertain to our body, and should we live outside of any society, or in the forest, we would still have these desires. The next stage of the development of the egoism is aspiration for wealth. Following this stage is the desire is for power, glory, and fame (combination of these). And finally, the desire that is the highest in our world, the desire for knowledge.
After having tried all these desires in the course of thousands of incarnations, after descending into our world thousands of times, a person reaches a state called recognition of Evil. In other words, each of us accumulates inner record which convinces us that nothing we do will give us pleasure.
Courtesy of http://www.youtube.com/watch?v=1JjC2nW61lU