Now if one infers from the existence of things in the world to their cause, this does not belong to the natural but to the speculative use of reason; for the former does not relate the things themselves (sub stances) to any cause, but relates to a cause only what happens, thus their states, as empirically contingent; that the substance itself (the matter) is contingent as to its existence would have to be a merely specA ulative cognition of reason.