On one level, the will to power is a psychological insight: our fundamental drive is for power as realized in independence and dominance. This will is stronger than the will to survive, as martyrs willingly die for a cause if they feel that associating themselves with that cause gives them greater power, and it is stronger than the will to sex, as monks willingly renounce sex for the sake of a greater cause. While the will to power can manifest itself through violence and physical dominance, Nietzsche is more interested in the sublimated will to power, where people turn their will to power inward and pursue self-mastery rather than mastery over others. An Indian mystic, for instance, who submits himself to all sorts of physical deprivation gains profound self-control and spiritual depth, representing a more refined form of power than the power gained by the conquering barbarian.
On a deeper level, the will to power explains the fundamental, changing aspect of reality. According to Nietzsche, everything is in flux, and there is no such thing as fixed being. Matter is always moving and changing, as are ideas, knowledge, truth, and everything else. The will to power is the fundamental engine of this change. For Nietzsche, the universe is primarily made up not of facts or things but rather of wills. The idea of the human soul or ego is just a grammatical fiction, according to Nietzsche. What we call “I” is really a chaotic jumble of competing wills, constantly struggling to overcome one another. Because change is a fundamental aspect of life, Nietzsche considers any point of view that takes reality to be fixed and objective, be it religious, scientific, or philosophical, as life denying. A truly life-affirming philosophy embraces change and recognizes in the will to power that change is the only constant in the world.