Reality is some rule that is always true. The rule never changes and by applying the rule we get what the reality is. For Schopenhauer it is the will, for Hegel it turns out to be the spirit which in turn becomes strangely enough power for Nietzsche. To reduce the reality to simple unchanging abstract or concrete thing, solves the complicating problems if we use Mathematics instead.
I wonder what could be the opposite for Schopenhauer that would complement the reality yet give an opposite view. Strangely I come up with a term fictional substance which I put up for mind. Does Schopenhauer mean will as the opposite of mind? How could otherwise he conclude will as representing the underlying representation of the world. We need mind to describe the relation it has with the world and for Schopenhauer it is defined by the will itself.
What I mean by fictional substance is that mind makes abstractions that are not concrete and has no clear framework in the world to which these abstractions are applied. Yet the abstractions clearly define the reality. So what could the fictional substance that erects fiction about the reality mean? Suppose I see a house, I already have an abstraction for the house and it is applied to the reality to define the house in question.
How Hegel defines the world through spirit? Similarly we could understand the world through fictional substance. What essentially we find in reality is fiction to the dual nature of matter. I cannot ascertain the reality I could only approximate through the use of language what it is out there and that is pure fiction, a figment of mind while consciousness stands by to tell the fiction is real and hence what we see is an illusion.