What theory does the narrator discuss in the opening pages of The Imp of the Perverse?

The narrator begins by discussing a theory that all phrenologists and metaphysicians have overlooked. He explains that man has organized things in such a way as to "dictate purposes to God" (pg. 222), for example, we decided that God wants us to eat, so we assigned purpose to an organ that we believe God uses to compel us to eat. He feels it would have been wiser to "classify ... upon the basis of what man usually or occasionally did ... rather than on the basis of what we took it for granted the Deity intended him to do" (pg. 223). He feels that if we are not even able to understand God in simple areas, there is no way we can understand God in important matters.