 Lefèvre’s natural philosophy is also distinctive for its attention to mathematical examples. In his Dialogues on Physics he displayed far more autonomy from Aristotle than he did in shorter introductions and paraphrases; and in the Introductory Dialogue on Difficult Physics (Dialogus difficilium physicalium introductorius) he began squarely with the problem of quantity. While never departing dramatically from the Aristotelian discussion of matter, weight, rarefaction and condensation, and the intension and remission of qualities, at each step, Lefèvre offers points, lines, and ratios as examples. An interlocutor marvels that he has learned to “philosophize about qualities through quantities” (per quantitatem de qualitate philosophor, Lefèvre 1502a: 146v).