And now i see i forgot about the dreams...
How can we be sure when we are awake or when we are dreaming? Like... for me we "know" we are awake because we remember all the times we were awake before, we remember all this times as a continuous thing, so we conclude that we are actually awake.
But if every night we had a dream where we could remember all the dreams we had before, exactly like we can remember all the things that happened when we were awake? How could we be sure that we were into a dream?
What if, every night, we dreamed we lived in another place, with another people, etc, and every night we dreamed with this same place, and with the same people, and remembered what we did in the day before? How could we know it was a dream? Or how could we be sure that this was not the "reality", and what we call waking reality were not only a dream in this (other) reality?