Didascalicon, Book III: the art of study (discipline and method)
Chapter X. On the manner of reading
The manner of reading consists in dividing. Every division begins from the finite and proceeds to the infinite. Every finite thing is better known and comprehensible by knowledge. Doctrine, moreover, begins from the things that are better known; and through the knowledge of these it reaches the knowledge of those that lie hidden. Besides, we investigate by reason, to which it properly belongs to divide, when we descend from universals to particulars by dividing, and by investigating the natures of individuals. For every universal is more determinate than its particulars. When we learn, therefore, we ought to begin from those things which are better known and determined and comprehensive; and so, descending little by little, and distinguishing each by division, investigate the nature of the things contained.