 In context, Aristotle is explaining that a fraction of a force many not produce the same fraction of motion. For instance, while 100 stevedores can tow a barge, one might not get it to move at all, let alone 1/100th of the speed; so given as much time as you like he may not move it as far as the 100. (We describe this fact as the effect of friction.) Similarly, just because a falling bushel of millet makes a whooshing sound as it falls, it does not follow that each individual grain would, or does: given as much time as you like it won’t move the same amount of air as the bushel does. However, while refuting this premise Aristotle does not explain what role it played for Zeno, and we can only speculate. It’s not even clear whether it is part of a paradox, or some other dispute: did Zeno also claim to show that a single grain of millet does not make a sound? One speculation is that our senses reveal that it does not, since we cannot hear a single grain falling. Then Aristotle’s response is apt; and so is the similar response that hearing itself requires movement in the air above a certain threshold. 