The Greatest Power On Earth

What is the greatest power on earth? 

One cannot see it, cannot measure it, cannot taste, cannot touch it, cannot see it and cannot hear it. It controls forces that move mountains, destroys peace and harmony, gives peace and harmony, it divides nations, states and communities. It injures families. It heals families. It can destroy the relationship with yourself, it can heal your relationship with yourself. When lost feels intolerable, when found gives peace - if it has peace with itself. It never turns off but can be stilled, can be aware of itself but most often goes unaware of itself creating havoc and pain for many including itself. It controls hate, fear, anger, guilt and shame. It is influenced by rhythms and cycles of nature but often is unaware of those cycles. It is influenced by light and dark. It wants pleasure more than pain but it is often the painful things that give it the most growth and satisfaction. Constant pleasure will drive it to insanity. It is often inflexible but when changed, changes the world. It is often hurt by nothing, in fact cannot tolerate nothing so makes nothing something. It has never been defined in its full context yet everyone knows exactly what it is. It creates laughter, tears, joy and pain. It can hold a conversation with the body that results in death or life.  It can hold a conversation with God and yet cannot comprehend God, but it can know God. It can enslave itself and yet it can free itself. It can make freedom frightening and slavery tolerable and safe.

What am I????