 It is not easy, however, to see what exactly “quantities” mean in this context. Some clarification can be gained from his argument for why quantities in a subject are limited by their contrary, which he illustrates with a quasi-geometrical figure representing the twin scales of hot and cold mentioned above. He imagines a range of heats in an object, from minimum to maximum heat, arranged along a line (a…k in the figure below). Then, he uses a reductio ad absurdum: if the smallest amount of coldness (l) from some other object (l…u in the figure below) were to be added to the maximum heat (k), a new degree of heat (x) would have to be added in the original object to create a new maximum.