The Ka (k3) was the concept of life force, the difference between a living and a dead person, death occurring when the ka left the body. The Ka was thought to be created by Khnum on a potter's wheel, or passed on to children via their father's semen.
The Egyptians also believed that the ka was sustained through food and drink. For this reason food and drink offerings were presented to the dead, though it was the kau (k3w) within the offerings (also known as kau) that was consumed, not the physical aspect. The ka was often represented in Egyptian iconography as a second image of the individual, leading earlier works to attempt to translate ka as double.
Julian Jaynes in his theoretical work The Origin of Consciousness in the Breakdown of the Bicameral Mind suggests that the "ka" originally was a hallucinated god-voice similar to that experienced in schizophrenia. According to his theory, most people were not fully conscious in the early ancient period, and hence his theory is regarded as fringe by the mainstream.
Giacomo Borioni proposes in his work "Der Ka aus religionswissenschaftlicher Sicht" that, according to Friedrich Junge, the Ka was the "self" of a human being.
"If I feel it is neccessary to talk down to you I will, and I do not care if it hurts your feelings... don't talk about shit you don't understand" -Ike