 Lefèvre’s textbooks were designed to help students gain access to Aristotle by quickly familiarizing them with the elementary definitions of each discipline and setting these in a larger schematic framework. In a comment on Aristotle’s Politics, he stressed that the integrity of different disciplines requires identifying the components proper to each—for example, the point in geometry, the monad in arithmetic, or the letters which make up words in grammar (1506: a2v). This respected Aristotle’s own methodical admonition not to make the mistaken assumption that conclusions from one discipline could be applied to another—his prohibition of metabasis. Similarly, from his earliest writings, Lefèvre insisted that each discipline should follow a distinctive kind of reasoning: thus