Human beings have brains. A natural evolution stemming from the creation of a nervous system, which we find is all higher animals. The assumption from this fact is to suggest we are ruled by these brains.
So what rules the brain?
I am not sure of the order of importance but my list includes: the need to eat, the need to survive,the need to sleep,the need to have status, the need to feel wanted, the need to procreate … the point is the things that rule our brains have no reasoning behind them, just the evolutionary necessity that helps the human survive in society and in nature.
Now we have these aspects of our being we rationalise them, after the fact. We have to deal everyday with our animal selves, not our thinking selves. In this is the core deficiencies in our dealings with each other and the world around us.