The ego is essentially a separate sense of self. It is comprised of anything you identify yourself with. To be able to comprehend of yourself as a unique thing within a system, you have to perceive yourself and then define yourself as different to other things within the system. You cannot conceptualize of what you are unless you conceptualize of what you are not. An easier way of understanding this is to say that you cannot conceptualize of yourself as “Joe” until you are aware that you are not “Nancy”. This means the ego only exists in a state of comparison. It cannot exist without comparison. This process of individualization benefits us in certain ways. But there is a price to it as well… Separation. When we conceive of ourselves as a separate self, we are immediately not a part of anything we define as “other”. This is the true origin of loneliness.