the significance of consciousness

We experience the world, reality or whatever, through our brains. Everything we know has been processed, filtered, made sense of, by a bundle of electrical impulses. The world, as we know it at least, is... basically nothing, empty space in an atom, chemicals working together to create... us? So, tell me, what really makes the world real?

Because for me, I can't seem to find a difference between dreams and our so-called real world. I experience both through my brain, and they both feel entirely real in the moment.

So what's different?? Consciousness? How do we know that we're really alive?