Bradwardine rejected four opinions concerning the link between power, resistance, and speed on the basis that were inconsistent with Aristotle's or because they did not align with what could be easily observed regarding motion. He does this by examining the nature of ratios. The first opinion Bradwardine contemplates before rejecting is one he attributes to Avempace that states " that speeds follow the excesses of motive powers over resistances", following the formula (V ∝ [M−R], where V = speed M = motive power, and R = resistance). he second opinion follows the formula (V ∝ [M−R]/R), which states "that speeds follow the ratio of the excesses of the motive over the resisting powers to the resisting powers". Bradwardine claims this as the work of Averroes. The third opinion concerns the traditional interpretation of the Aristotelian rules of motion and states "that the speeds follow the inverse of the resistances when the moving powers are the same (V ∝ 1/R when M is constant) and follow the moving powers when the resistances are the same (V ∝ M when R is constant)". His last rejection was "that speeds do not follow any ratio because motive and resistive powers are quantities of different species and so cannot form ratios with each other". "Bradwardine's own rule is that the ratio of speeds follows the ratios of motive to resistive powers."