If you close down and put yourself into a box, associating yourself with some 'part' of the environment that is different or separate from other parts, your awareness becomes blocked. You are no longer aware of what is outside the box, so you think that your awareness is limited TO the box, and therefore this is the extent of who you are. Now you equate yourself with the box and think you are it.
So you come into this body and you think that you are this body, only this body, and nothing else. And that's fairly natural given you have fallen for the ILLUSION that you are only this self and not any other selves. The body seems to suggest that you are separate from your brother, and that who you are is NOT them in any way.
When you then look out at the world you see a world of separate individuals, where you do not see yourself in them. You see the form of their body and you think that is what defines their identity, because you're focussing on what is different and unique about them.
But these differences and uniquenesses are actually what keep people separate, and what reinforces the ILLUSION that they, and you, are not whole, and not one.
This isn't your true identity, or theirs.
When you take the lid off the box and stop believing the illusions that suggest you are not other people, that there is no oneness anywhere, which is what this entire physical world was set up to try to achieve, you would become aware of a greater sense of self. This sense of self would accompany the amount of AWARENESS that you have that there is ONE IDENTITY spanning multiple individuals.
Whatever size box you are inside of, and are aware of, that dictates the limits and confines of your identity. So if you think you are your body, you are very limited indeed. You will simply not have the awareness that you are everyone else. Or that you are part of God. And since that oneness is outside your awareness, you will not experience it as your SELF, and will not believe it is real.
Therefore, there is a very intimate relationship, a literal connection, between what you are are AWARE of, and what your IDENTITY is.
If your awareness is small a limited by differences, appearances and forms, blinded by form, so too will your sense of identity shrink down to fit inside that definition. Those blocks to awareness, those obstacles to peace, will shut out awareness of any kind of 'larger sphere' or greater scope of awareness that you might experience, or any sense of being joined to or sharing SELF with others.
But your sense of self really is derived from how INCLUSIVE your awareness is. When it is very exclusive and separation-oriented, you will experience 'your self' as small and fragile and afraid. But when your awareness becomes more inclusive, you will experience yourself as larger, expansive, joined, open and united with others.
The ultimate sense of self then will be when you come to no longer be deceived by appearances of form, no longer deceived by illusions of separation, and access a shared unified consciousness that spans everyone and is the same in everyone. The ONE SON OF GOD. The Christ consciousness. This IDENTITY as Christ is experienced as a result of the AWARENESS that there IS christ, that awareness includes everyone and that everyone is a part of and SHARES this awareness.
So then you, as the awareness of Christ, an awareness of oneness, of being the one Son of God, the single unified creation, will be inclusive of all seemingly separated 'sons' in the brotherhood. This will literally mean, that everyone else IS YOU. Is part of this shared wholeness. That we are literally all one self.
This 'identity' that we call self is therefore completely dependent upon WHAT it is that we are aware of. The whole, or the part. Being aware only of the part is what we call an ego identity because it is limited and blocked and includes unconsciousness - a lack of awareness. Ignorance. But you will still think of this - whatever the extent of your awareness is - as your 'self'. Yet as your awareness expands so too is your 'self' expanding, letting go of the isolated separated ego self and opening up to a bigger, shared self that is the same for all of us, in which we are all one family. Not just a family of equal or separately at-peace beings, but in fact FAR more unified than this - a true family where we literally ARE each other.
Eventually the brotherhood will unite in this oneness and we will all unify in the ONE SELF. One with God. Inclusive of all.