We could, in theory, have been born with a consciousness that distances itself from our neurological, biological self. We could have brains and body that react to stimuli, feel emotions and reactions, reason, contemplate (cognitively) yet not also possess the part of consciousness that feels unattached to the body.
But instead we all have a consciousness that believes itself to belong to who we are. The “I” consciousness happens. We could be observers, only, of ourselves, like we are of every other person and thing, but instead we are attached to that remote part of our consciousness. In fact life would be easier much of the time, if we felt separate from our emotions and physical parts of our body, so why then, doesn’t it happen that way?
Our consciousness is us, our spirit. We have a spiritual identity which is us. Our body is only a tool we use to deal with this physical world. Before we were born into this physical world we already existed, we had a life, we had intelligence. When our physical body dies and is buried, our spirit will continue to exist and we will retain all we have learned as we continue on with our eternal progression.
Your theory isn’t new, but I think this part of it may be: “yet not also possess the part of consciousness that feels unattached to the body.”
If that was the case, we would be the brain in the vat, the people in the Matrix, and unless you were some how extremely intuitive as Leo was in believing there was something called the Matrix that kept him searching for it, unless that, you would never know that your consciousness was not connected. There would be no way to prove it.
But I think realistically we must admit that is as distant a possibility as that our hands and feet and head are not connected either, and that we simply do not also possess the part of consciousness that feels them unattached to the body.