 Hume portrays his scientific study of human nature as a kind of mental geography or anatomy of the mind (EHU 1.13/13; T 2.1.12.2/326). In the first section of the first Enquiry, he says that it has two principal tasks, one purely descriptive, the other explanatory. Mental geography consists in delineating “the distinct parts and powers” of the mind (EHU 1.13/3). While everyone can make some sense of the basic distinctions among the mind’s contents and operations, more fine–grained distinctions are harder to grasp.