How is the individuality of Man formed, the Ego?
We all originate from life itself, from a special original energy, the source of life, the source from where all life-power and joy of life originate.
This energy creates, through its self-production, its own substance, namely sensation, observance and thinking.
It was this substance Descartes called the thinking substance (res cogitans), which is standing as opposed to the outstretched substance (res extensa).
The thinking substance you could call the abstract side of Man (logos).
The action and conduct of life is the practical, or concrete side (bios).
There exists of course not such an absolute division. Nonetheless it is the thinking´s self-production which creates the separation of the observer and the observed, the split in the thinker, who is standing outside his own actions and conduct of life, who distances himself from them, and relates thinking to them.