Just as one sees his nose best in a mirror, removed to half the optimum focal distance, so also he best identifies his sense data by reflecting them in external objects.

• 正像人只有通过镜子（移至焦点距离的一半）才最能看清自己的鼻子一样，同样，他也只有借助对外部对象的观照才能最好地认清他的感觉材料。