"Nothing exists; all is a dream. God--man--the world--the sun, the moon, the wilderness of stars--a dream, all a dream; they have no existence. Nothing exists save empty space--and you!"
What a sad, sad conclusion. Even further he expands on this thought and condemns God, while at the same time denying His existence. Logic doesn't allow for this, if Twain is honest. And if his conclusion is true, then it is self-contradicting. The simultaneous denial and condemnation of God is ridiculous. The phrase/thought/idea of "all reality is a dream", by existing in order to communicate non-existence, refutes itself. If nothing is real, if all is a dream, then dream up something on command! Tell the thoughts of another person to be something other than they are. Tell history to reverse itself. End all the pain and suffering in this world. Of course, you cannot do that. You have reality to deal with.
