I disagree with the simplification of what it constitutes to be human.
Humans come in many various guises and to attempt to quantify what makes us so varied cannot be summed up with a few sentences.
I know what I am and I am what I am because that's what I want to be.
To live a completely egotistical existence would mean the extinction of the human race , man alone is a vulnerable creature and it is only the ability to socialise that has allowed us to become the dominant species we are.
If man had never learned to work together then we would probably still be hiding in caves from the nasty critters that would just love a little human .
Even something that is considered an everyday thing like a gun has taken many people to create and develop.