But do the people in your dreams ponder philosophy and question their own existance?
It's like, in the Matrix, how do the real people know they're real and not just programs created by the machines? They live in a totally fictional world. Everything they see, hear, touch, taste, and smell is fake. The people they meet may or may not be real, and even if they do exist, in reality they are nothing like what they see in the Matrix. Still, the ones that question this artificial world and learn the truth about the Matrix can be certain of their own existance, because if they were merely programs created by the machines they would never think this way.