Review:"The Universe is a Dream"

The author of this book claims that the universe we're experiencing is a dream and not a reality. Same belief can find in the movie "The Matrix".
In response to this claim, I should say that all human beings are alone and independent in their dreams. You experience life with your partner or family. But you are the only one experiencing what you see when you're asleep or in your dreams.
So if the universe was a dream, it would be to the number of all people living. But we all have a common picture of the universe in which we live. Windows Vista is common to all of us. We all know about World War II.
Can seven billion population of the world see a common dream?
So the universe isn't a dream.
Author may claim that seven billion population of the world is just a dream! And all these people come from your imagination.
The answer: If you believe your existence, I also believe in myself existence. And this means the separation. Separation means that you're an entity separate and independent from mine. But you and I have the same picture of the universe while we're separate and independent of each other.
Is the universe a dream?!

Critic to Existentialism

I read a book called “The Universe is a Dream”. This essay isn't about it. Maybe I write a critic about it someday. But it made me evaluate Existentialism's thoughts. A main part of these thoughts are as: the universe has no creator. Many philosophers such as Foucault, Niche and Kant had some theories in this case about ethics  and law etc. Although many of them where misbelievers, their theories weren't according to acceptance of not having a creator. But Existentialism's theory is according to have no creator. But we can't deny a source for this universe. What is that? 
God? Dialectical materialism? Or something else?
Existentialism can't answer this main question. They accept not having a creator for the universe as a reality without filling the source gap with something else. They then assert Existentialism according to this basis. Existentialism isn't a philosophy, it's only a literature and art thought.