Spiritual life is a struggle because, he or she has to swim opposite the direction of the river flow. To flow with the river is easy, but there is always bumps and humps of life, which is also sorrowful. The spiritual seeker has to go backwards to the "Source of the river" to extinguish the reflection of the Sun, the Ego. Because we have already seen that going backwards to the second stage of river, the reflection becomes less hazy and in the glacier stage there is no reflection of the sun but only pure awareness. This is the state of a self realized person.

      All beings proceed towards this state of self Realization, which is a process called evolution. Every being has that inherent tendency to reach that state of pure awareness and merge to the pure Consciousness. This is the propelling force for survival that is seen in all beings.  This Vedantic concept  took thousands of years in the west to be popularized by Charles Darwin.  However the evolution theory proposed by Charles Darwin is not complete because it only gives the answer of how through survival of fittest, evolution moves forward, but there is no explanation for a why does it have to occur.