...since your line of thinking is going in a different direction from what I thought. I guess I'm not familiar with the back story. The idea that only dreamed-of things are real sounds more like postmodernism than atheism (though admittedly there is probably some overlap). It reminds me of the distinction between signifiers (words) and the signified (ideas that represent reality). In this paradigm, the most we can hope to do is to describe the mental representation of reality as conveyed by our senses and apprehended by our minds. The objective reality never comes within our experience.
While there is some truth to that, I think it is overstated. If our senses and minds did not create at least a close approximation of reality, they would not have created a survival advantage and we would not have survived to this point. Most skeptical atheists, therefore, tend to believe in the objective reality of your example and assume that anything beyond our perception is imagined (something we are abundantly capable of doing) unless a real reason is found to accept it. What you are suggesting--that reality only consists of what is dreamed of, is a lot more like the ontological argument as proof of god: that if there is a word for something, it must be real. I refute that idea with one word: Godzilla.
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