Who is I? Who are we?

Who is US?

Who is us? What defines us? What makes us us, in comparison to the others??

First try:
I am us. Clearly, I am I. And whoever is not I, is not us. Their worlds are different, I cannot feel what they feel. Hence, they are not I. And they are not us.
However, why do we then extend the rights and duties we oblige from ourselves to others? Why do I feel that (some of) my family, friends, etc. deserve the same things I deserve? By extending these rights (and duties) to others, it becomes clear that I is not us. I form part of us. But I do not define the entire us.

Second try:
My family is us. Clearly, I form part of us. My family is the extension of myself, and I extend the rights to them that I want for me.
Yet again, why do I extend the rights to friends, and sometimes even to strangers? Why do I often feel bad when I do not extend these rights to someone? Besides, what should the defining criterium be if family were us? The definition of us if the family XYZ. Why not some other family? The mere arbitrariness of that definition of us makes me shiver.

Third (and fourth to tenth) try:
My nation is us. (My religion is us. My skin color is us. My region is us. My gender is us. My political party is us. My social class is us. My blood type is us.)
These are all extensions of I to some set of humans that share certain traits with me. However, in each of these definitions, the others are very much like us. Is someone becoming us if he moves to my region, nation? Converts to my religion? Adapts the same gender? It seems that all these classifications imply that there are others that are much more like me than some members of my group.

Eleventh try:
All humanity is us.
This seems like a reasonable assumption, immune to all the objections former definitions of us called for. However, what is the defining criterium?
Consciousness? What would we say about a human that is not conscious? Would it not be us? A human that walks like us, breathes like us, talks like us, feels like us. But doing all these things unconsciously. Would it seize being us? Probably not, in particular, if we consider that the degree of consciousness varies among humans.
The ability to feel pain and joy? What would we say about a human that cannot experience pain or joy? Would it stop being us? Would we apply different laws to them? Would it seize being us? Many people experience both pain and joy very differently. Who am I to judge?
Being alive? What would we say about a human that is not alive? Would it stop being us? What we stop extending the same rights to a person that is not alive than to ourselves? Apparently so…… What does that imply?

Twelfth try:
Everything alive is us.