Everything that you think you know, feel, understand and believe, rises in consciousness. The very feeling of the self is something that can be studied and observed.
You are the space where everything emerges. You are none of the things you think or believe, even the sense of an observer is an apparition. Most of these manifestations are transitory. They change, disappear and morph into something else. Nothing is permanent. Do not grow too attached to any of these manifestations, even to the fleeting feeling of self.
A thought arises completely on its own, without your concept of "you" having taken any action. It emerges, seemingly out of nothing. And after an instant, it disappears back into the void. "I" had nothing to do with this, all I did was pay attention. The fact that this is something that can be observed and experienced, by anyone, is empirical evidence that we are not our thoughts, or any other of the things that arise in this space called consciousness. There is no need to define ourselves based on our thoughts. They come and go, rise and fall, completely independent of our volition.
We are the space that remains, that open space where everything else arises and passes. This space feels, at times, so wide, almost infinite. Consciousness is the witness to everything as it comes and goes.
Where does the spatial limit to consciousness lie? How far does it extend? You can feel that it has no center, no gravity, it is an open expanse. But how far does it truly extend? It feels limitless, yes. But there is no way to know for sure. Because to feel this space as it is, you have to let go of the very tools you would need to understand it.