Broadening his analysis to include "objects' in general, Ryall demonstrates how Kant fails to trace the illusory appearance of celestial motion back to the motion of the observer, instead trying to gauge how the pure understanding can "transform" this appearance into an "objective experience". The reason Kant cannot appeal to the motion of the observer is quite simply because this never "appears' to the subject herself and so, without an appearance, there will be nothing for the understanding to judge. Because our transcendental faculties become operative only when applied to appearances, Ryall argues, reductio ad absurdum, that the full panoply of those "intuitions' and "concepts' which Kant claims are synthesised in constructing a world are incapable of delivering the scientific facts as we understand them.