 In Treatise I, Boethius develops this scheme. In especial, he distinguishes between predications in the categories of Substance, Quantity and Quality, which are proper and intrinsic, and those in the other six categories, excluding Relation, which he calls improper and extrinsic. The intuitive idea behind the distinction seems to be that predications in these other categories concern only how the subject relates to other things; only substantial, quantitative and qualitative attributes characterize the thing itself. Boethius goes on to say that, whereas all proper, intrinsic predications about God are substantial, extrinsic, improper predications about him are not: they do not concern what either God or his creatures are, but are rather about exterior things.