 Putting these pieces together we can see that “things in themselves” [Dinge an sich selbst] and (negative) “noumena” are concepts that belong to two different distinctions: “thing in itself” is one half of the appearance/thing in itself distinction, which Kant originally defined at A491/B519 in terms of their existence: appearances have no existence “grounded in themselves” while things in themselves do. “Noumena” is one half of the distinction phenomena/noumena which Kant characterizes at B307 as the distinction between what can be an object of our sensible spatiotemporal intuition and what cannot be an object of sensible intuition. (Kant here appears to overlook the possibility of objects of sensible but non-spatiotemporal intuition). One is a distinction in what ground the existence of objects; the other is a distinction in what kinds of intuition can present those objects. However, we can make a connection between them: things in themselves, the objects whose existence is “ground in itself”, and which appear to us in space and time, cannot be objects of any sensible intuition, so they are negative noumena. Whether, additionally, they are also objects of an intuitive intellect, is a separate matter. This is a point about the relations among these concepts; it holds whether or not they are possibly instantiated.