We just realise the immediate surrounding. But what is that, that surrounds the surrounding and why don’t we understand it? This would be explainable, by saying that we are the programmed projection of another world. Like a hologram which is projected and so is a programmation of what others invented. That would mean, that we would be projected not to think of the surrounding of our surrounding.
Still, as Moe says, our reality could be reality’s dream world. Aren’t we prisoners of our dreams and when we dream we see a part of ‘real’-reality? The reality which we will understand by dying and waking up and living in it?
Also it could be, that we would be just living in one room. We live in a room which adapts to our situation. Everytime we think we open a door, we would open an imagined door and go back to the same room, which just seems different to us.
We arranged the room with few things. A table, a shower, a bed, a cabord etc. Everytime we open the door, we just notice a part of the room’s existing things. Therefore a schizophrenic would realise an extended part of reality, because they could hear the existing voices which we just could not here.
We have to define Reality. But we can just define, what is for us understandable. Like the universe. We define it as endless, just because we can not measure it. If we could measure it, it would not be endless and understandable. Therefore we could define it. But is anything definable? Like a blanket, a blanket is something that covers us. But what covers us? The sky is also covering us, but is it therefore a blanket? And does something cover us, just because we feel covered? And isn’t it that we feel covered when we are not and we are covered when we do not feel like being it?