Didascalicon, Book III: the art of study (discipline and method)
Chapter I. On discipline and its division
Philosophy is divided into theoretical, practical, mechanical and logical. The theoretical is divided into theology, physics and mathematics. Mathematics into arithmetic, music, geometry (and astronomy). The practical into solitary, private and public. The mechanical is divided into wool-working, armament, navigation, agriculture, hunting, medicine and the theatrical. Logic is divided into grammar and the art of discoursing. The art of discoursing is divided into demonstration, the probable and the sophistical. The probable is divided into dialectic and rhetoric. In this division only the divisive parts of philosophy are contained; there are still further subdivisions of these parts, but these may suffice for now. In these, then, if you look only to the number, there are twenty-one; if you wish to reckon the degrees, you will find thirty-eight. The authors of these sciences are read to be various. Some discovered the arts by beginning them, others by increasing them, others by perfecting them, and so for the same art several authors are often reported. Of these I will number below the names of a few.