Chakravartty began his study with rough characterizations of realist and anti-realist valuations of theories. Anti-realists believe "that theories are merely instruments for predicting observable phenomena or systematizing observation reports;" they assert that theories can never report or prescribe truth or reality "in itself." By contrast, scientific realists believe that theories can "correctly describe both observable and unobservable parts of the world." Well-confirmed theories—"what ought to be" as the end of reasoning—are more than tools; they are maps of intrinsic properties of an unobservable and unconditional territory—"what is" as natural-but-metaphysical real kinds.