If, then, the comings-to-be which happen to the matter start from the contraries, and proceed either from the form and the possession of the form or from a privation of the form or shape, clearly all contrariety must be privation, but presumably not all privation is contrariety (the reason being that that has suffered privation may have suffered it in several ways); for it is only the extremes from which changes proceed that are contraries.
Bestalde, baldin eta genesiak-materiari dagokionez-kontrakoetatik sortzen badira-sortu ere formatik, hots, forma edukitzetik zein formaren eta egituraren ezaren batetik-, argi dago kontrakotasun oro eza izango dela, baina eza oro ez da, 15) ziurraski, kontrakotasuna izango (zerbaiten eza duenak zentzu askotan izan dezakeelako zerbaiten eza), kontrakoak baitira muturrekoak, zeintzuetatik aldaketan sortzen diren.