Geometrically a unicursal curve may be traversed by the continuous motion of a moving point. 几何上，一条单行曲线可以由一个动点的连续运动描出。
But in order to arrive at the laws of the continuous motion due to the sum of all these individual wills, the human mind assumes arbitrary, disconnected units. 但为了理解人们的随意行为的总和所构成的连续运动的规律，人类的智慧便假设出了随意可以截取而互不连贯的单元来。
