 According to Aristotle (Physics VIII), motion occurs only if the ratio of acting capacity (a force F) to passive capacity (a resistance R) is a ratio of major inequality, i.e., when it is greater than 1. Kilvington maintains that any small excess of force over resistance suffices for motion to commence and continue; thus, whenever force is greater than resistance, motion occurs (DM: 215–25, 252–58). This assumes that force (an active capacity) is bounded by a minimum upon which it cannot act (minimum quod non), i.e., by the resistance that is equal to it (DM: 225–29, 258–59). For a passive capacity, Kilvington accepts the minimum quod sic limit “with respect to circumstances”. He accepts Aristotle’s claim that to establish a limit for Socrates’ passive capacity of vision, we should point to the smallest thing he can see. However, it also happens that we cannot see such a great thing as a cathedral if we are too close to it. Therefore, a passive capacity cannot be described by a minimum quod sic limit in each case (DM: 229–33, 259–62).